fix: Check that content is not None before setting to internal_monologue

[mattzh72]

Check that content is not None before setting to internal_monologue. This is causing intermittent errors sometimes with our testing, where sometimes the model does not use the content field:

=========================== short test summary info ============================
FAILED tests/test_tools.py::test_create_agent_tool[client0] - ValueError: Failed to send message: {"detail":"1 validation error for InternalMonologue\ninternal_monologue\n  Input should be a valid string [type=string_type, input_value=None, input_type=NoneType]\n    For further information visit https://errors.pydantic.dev/2.9/v/string_type"}
================== 1 failed, 2 passed, 36 warnings in 16.10s ===================

Additionally, we also search for inner_thoughts in the function args - community members noted that inner thoughts can sometimes appear in function args instead of the content field for function calls.

[cpacker]

@mattzh72 can you revise to basically just add a conditional? So remove the added code, and modify the delete code to just be wrapped by a conditional

[cpacker]

LGTM!