fix: accept dict tool arguments in ChatMessage.from_openai_dict_format

[MohammadHijjawi97]

Related Issues

No existing issue. This PR includes a regression test for the crash.

Proposed Changes:

Proposed Changes:

ChatMessage.from_openai_dict_format always passed tool-call arguments to json.loads. Some OpenAI-compatible servers already send a parsed dict, which raised TypeError. Invalid JSON strings also crashed. Accept a dict payload, treat empty/null/invalid JSON as {}.

How did you test it?

Added unit tests for dict arguments and invalid JSON. Existing empty/missing argument tests still pass.

Notes for the reviewer

Checklist

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• I have updated the related issue with new insights and changes.
• I have added unit tests and updated the docstrings.
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• I have documented my code.
• I have added a release note file, following the contributors guidelines.
• I have run pre-commit hooks and fixed any issue.

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