Python: fix: Remove wrong response_format override in AzureChatPromptExecutionSettings class

[danigian]

Motivation and Context

This change is required to fix #5997

Description

The change is removing the wrong response_format override in AzureChatPromptExecutionSettings class. The PR is also adding a unit test covering the case where response format is defined.

The changes were successfully tested against an Azure OpenAI instance with a gpt-4o deployment by specifying an AzureChatPromptExecutionSettings like follows:

execution_settings =  AzureChatPromptExecutionSettings(
        service_id=service_id,
        ai_model_id=ai_model_id,
        max_tokens=1000,
        temperature=0.2,
        response_format={"type": "json_object"},
    )

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/prompt_execution_settings
azure_chat_prompt_execution_settings.py	62	1	98%	96
TOTAL	6126	881	86%

Python 3.10 Unit Test Overview

Tests	Skipped	Failures	Errors	Time
1394	1 💤	0 ❌	0 🔥	18.845s ⏱️

[eavanvalkenburg]

Thanks for this, looks good!