[smithy-rs] Fix server code generation of @httpPayload-bound constrained shapes (#2584)

The issue is we're not changing the return type of the payload
deserializing function to be the unconstrained type (e.g. the builder in
case of an `@httpPayload`-bound structure shape) when the shape is
constrained.

Yet another example of why code-generating `constraints.smithy` (see
#2101)
is important.

Closes #2583.

## Testing

The added integration test operation fails to compile without this
patch.

## Checklist
<!--- If a checkbox below is not applicable, then please DELETE it
rather than leaving it unchecked -->
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the
smithy-rs codegen or runtime crates

----

_By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice._

Author: david-perez

sdk/amplifyuibuilder/src/protocol_serde/shape_component.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_component_payload(input: &[u8]) -> Result<crate::types::Component, aws_smithy_json::deserialize::error::DeserializeError> {
+pub(crate) fn de_component_payload(input: &[u8]) -> Result<crate::types::Component, aws_smithy_json::deserialize::error::DeserializeError> {
     let mut tokens_owned = aws_smithy_json::deserialize::json_token_iter(crate::protocol_serde::or_empty_doc(input)).peekable();
                         let tokens = &mut tokens_owned;
     let result =

sdk/amplifyuibuilder/src/protocol_serde/shape_create_component_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::create_component::CreateComponentError> {
+pub(crate) fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::create_component::CreateComponentError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_component::de_component_payload(body).map_err(crate::operation::create_component::CreateComponentError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_create_form_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Form>, crate::operation::create_form::CreateFormError> {
+pub(crate) fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Form>, crate::operation::create_form::CreateFormError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_form::de_form_payload(body).map_err(crate::operation::create_form::CreateFormError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_create_theme_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Theme>, crate::operation::create_theme::CreateThemeError> {
+pub(crate) fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Theme>, crate::operation::create_theme::CreateThemeError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_theme::de_theme_payload(body).map_err(crate::operation::create_theme::CreateThemeError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_form.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_form_payload(input: &[u8]) -> Result<crate::types::Form, aws_smithy_json::deserialize::error::DeserializeError> {
+pub(crate) fn de_form_payload(input: &[u8]) -> Result<crate::types::Form, aws_smithy_json::deserialize::error::DeserializeError> {
     let mut tokens_owned = aws_smithy_json::deserialize::json_token_iter(crate::protocol_serde::or_empty_doc(input)).peekable();
                         let tokens = &mut tokens_owned;
     let result =

sdk/amplifyuibuilder/src/protocol_serde/shape_get_component_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_component_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::get_component::GetComponentError> {
+pub(crate) fn de_component_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::get_component::GetComponentError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_component::de_component_payload(body).map_err(crate::operation::get_component::GetComponentError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_get_form_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_form_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Form>, crate::operation::get_form::GetFormError> {
+pub(crate) fn de_form_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Form>, crate::operation::get_form::GetFormError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_form::de_form_payload(body).map_err(crate::operation::get_form::GetFormError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_get_theme_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_theme_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Theme>, crate::operation::get_theme::GetThemeError> {
+pub(crate) fn de_theme_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Theme>, crate::operation::get_theme::GetThemeError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_theme::de_theme_payload(body).map_err(crate::operation::get_theme::GetThemeError::unhandled)
     }).transpose()

sdk/amplifyuibuilder/src/protocol_serde/shape_theme.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_theme_payload(input: &[u8]) -> Result<crate::types::Theme, aws_smithy_json::deserialize::error::DeserializeError> {
+pub(crate) fn de_theme_payload(input: &[u8]) -> Result<crate::types::Theme, aws_smithy_json::deserialize::error::DeserializeError> {
     let mut tokens_owned = aws_smithy_json::deserialize::json_token_iter(crate::protocol_serde::or_empty_doc(input)).peekable();
                         let tokens = &mut tokens_owned;
     let result =

sdk/amplifyuibuilder/src/protocol_serde/shape_update_component_output.rs

@@ -1,5 +1,5 @@
 // Code generated by software.amazon.smithy.rust.codegen.smithy-rs. DO NOT EDIT.
-pub fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::update_component::UpdateComponentError> {
+pub(crate) fn de_entity_payload(body: &[u8]) -> std::result::Result<std::option::Option<crate::types::Component>, crate::operation::update_component::UpdateComponentError> {
     (!body.is_empty()).then(||{
         crate::protocol_serde::shape_component::de_component_payload(body).map_err(crate::operation::update_component::UpdateComponentError::unhandled)
     }).transpose()