chore: Add support for typed maps in autogen

[manupedrozo]

Description

Description

Adding a custom Map terraform type for autogen usage following the work done at #3830 which added a custom NestedMap type.

The new customtypes.Map type is used for Terraform attr types, e.g. types.String.

Also:

• Fixed a panic that occurred when unmarshaling zero-initiated nested attributes.
• Enabled custom types for remaining resources: cluster_api & stream_instance_api.

Custom TF types docs: https://developer.hashicorp.com/terraform/plugin/framework/handling-data/types/custom

Link to any related issue(s): CLOUDP-353171

Type of change:

• Bug fix (non-breaking change which fixes an issue). Please, add the "bug" label to the PR.
• New feature (non-breaking change which adds functionality). Please, add the "enhancement" label to the PR. A migration guide must be created or updated if the new feature will go in a major version.
• Breaking change (fix or feature that would cause existing functionality to not work as expected). Please, add the "breaking change" label to the PR. A migration guide must be created or updated.
• This change requires a documentation update
• Documentation fix/enhancement

Required Checklist:

• I have signed the MongoDB CLA
• I have read the contributing guides
• I have checked that this change does not generate any credentials and that they are NOT accidentally logged anywhere.
• I have added tests that prove my fix is effective or that my feature works per HashiCorp requirements
• I have added any necessary documentation (if appropriate)
• I have run make fmt and formatted my code
• If changes include deprecations or removals I have added appropriate changelog entries.
• If changes include removal or addition of 3rd party GitHub actions, I updated our internal document. Reach out to the APIx Integration slack channel to get access to the internal document.

Further comments

[AgustinBettati]

As these were the last usages of use_custom_nested_types, can we remove it from config_model.go? Ok if preference for separate PR, just want to make sure we remember removing and its associated usage.

[manupedrozo]

Will be removed in the cleanup task yes CLOUDP-352973

[AgustinBettati]

q: Is there a reason why this implementation deviates from other implementations which check for null?

if v.ElementType(ctx) == nil {

[manupedrozo]

Unlike other types, which just return the underlying elementType, the basetypes.ObjectValue.AttributeTypes() implementation creates and returns a map:

// AttributeTypes returns a copy of the mapping of attribute types for the Object.
func (o ObjectValue) AttributeTypes(_ context.Context) map[string]attr.Type {
	// Ensure callers cannot mutate the internal attribute types
	result := make(map[string]attr.Type, len(o.attributeTypes))

	for name, typ := range o.attributeTypes {
		result[name] = typ
	}

	return result
}

At which point, its better to compare against a zero-value.