Python: Fix schema handling. Fix function result return for type list.

[moonbox3]

Motivation and Context

Building the tools json payload from the kernel parameter metadata wasn't properly including an object of type array.

Description

Correctly include the object type array so that the tool call doesn't return a bad request. Add unit tests.

• Closes Python: Kernel functions cannot handle list parameters. #6367
• Closes Python: Openai spec plugin with array type arguments is recognized as string during functional calling. #6360
• Fixes the FunctionResult return for a type string -- if the FunctionResult is of type KernelContent then return the first element of the list, otherwise return the complete list.
• Fix the kernel function from method to include the proper type_object for the return parameter so that the schema can be created properly.
• Add retry logic for a sometimes flaky function calling stepwise planner integration test.
• Add a check during function calling that makes sure the model is returning the proper number of arguments based on how many function arguments are required.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[markwallace-microsoft]

Python 3.10 Test Coverage Report •

File	Stmts	Miss	Cover	Missing
semantic_kernel/connectors/ai/open_ai/services
open_ai_chat_completion_base.py	219	98	55%	98, 118, 143–147, 171, 175, 191–196, 213–241, 244–255, 273–280, 291–299, 315–322, 343, 351, 357–363, 375–381, 412, 451, 453–454, 459–464, 468–475, 479–491, 513, 522–531
utils.py	31	11	65%	20–30, 41, 60
semantic_kernel/connectors/openapi_plugin
openapi_manager.py	58	21	64%	92–125
openapi_parser.py	84	4	95%	69, 92, 95, 126
openapi_runner.py	99	64	35%	53–55, 61–62, 68–82, 86–102, 105–107, 110–112, 115–118, 126–169
semantic_kernel/connectors/openapi_plugin/models
rest_api_operation.py	124	52	58%	72–78, 81–98, 101–103, 106–119, 122–133, 136–148, 175, 191, 204, 238, 243, 247, 259, 275
rest_api_operation_run_options.py	6	2	67%	11–12
rest_api_uri.py	9	3	67%	14, 17–18
semantic_kernel/functions
function_result.py	30	9	70%	49, 51–52, 62–67
kernel_function_from_method.py	85	6	93%	129, 148–149, 155, 158–159
TOTAL	6078	869	86%

Python 3.10 Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1374	1 💤	0 ❌	0 🔥	15.312s ⏱️