Python: fix(python): Use AgentResponse.value instead of model_validate_json in HITL sample

[LEDazzio01]

Summary

Fixes #4396

The HITL guessing_game_with_human_input.py sample used model_validate_json() to manually parse the agent's structured output:

text = result.agent_response.text
last_guess = GuessOutput.model_validate_json(text).guess

Since the agent is configured with response_format=GuessOutput, the AgentResponse object already provides a .value property that returns the parsed Pydantic model directly:

last_guess = result.agent_response.value.guess

Changes

guessing_game_with_human_input.py

• Replaced GuessOutput.model_validate_json(text).guess → result.agent_response.value.guess
• Updated docstring comments to explain .value usage
• Removed unused text variable assignment

Notes

Other sample files (edge_condition.py, multi_selection_edge_group.py) also use model_validate_json with structured outputs, but their usage is in edge conditions and non-AgentExecutorResponse contexts (e.g. parsing from ChatClient.get_response().messages[-1].text), which are more nuanced. This PR focuses on the primary file called out in the issue. A follow-up PR can address the remaining samples if desired.

[Copilot]

Pull request overview

Updates the Python HITL guessing game sample to use the framework’s structured-output accessor (AgentResponse.value) instead of manually parsing JSON with model_validate_json, aligning the sample with current structured output ergonomics.

Changes:

• Replaced manual JSON parsing (GuessOutput.model_validate_json(...)) with result.agent_response.value.
• Updated inline documentation/comments to describe .value usage.
• Removed the now-unneeded intermediate text variable.

[LEDazzio01]

Great catch! Pushed commit a76092d with the safety guard:

agent_value = result.agent_response.value
if agent_value is None:
    raise RuntimeError(
        "AgentResponse.value is None. Ensure that the agent is invoked with "
        "options={'response_format': GuessOutput} so structured output is available."
    )
last_guess = agent_value.guess

This ensures a clear error message instead of an AttributeError if .value is None due to response_format not being propagated through the streaming path.