Python: Support Auto Function Invocation Filter for AzureAIAgent and OpenAIAssistantAgent

[moonbox3]

Motivation and Context

The server-side agents like AzureAIAgent and OpenAIAssistantAgent do not support the Auto function invocation filter. Although we return intermediate step results, like FunctionResultContent, as part of the on_intermediate_steps callback, this didn't allow for developers to configure a filter to return the result as-is, or modify the result as part of the filter.

Description

Add support for the auto function invocation filter for the AzureAIAgent and OpenAIAssistantAgent.

• Closes Python: Azure AI Agent - Prevent LLM from modifying the FunctionResult #11054
• Closes Python: improve ChatCompletionAgent & getting started with agent READMEs #11456
• Adds samples on how to configure the filter for both agent types, and how to configure the callback to show the various content types.

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 Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3418	5 💤	0 ❌	0 🔥	1m 40s ⏱️