Fix final_answer issue in e2b_executor

[keetrap]

• Closes use_e2b_executor=True does not seem to work #244
• I'm not sure if this is the best fix. Please review and suggest any improvements.

Additional Context:

• While working on the fix, I encountered an installation issue with the current PyPI release on smolagents on e2b.
• I tested the changes by removing torchvision and transformers which allowed the package to be installed successfully.

[keetrap]

@aymeric-roucher @albertvillanova
Please let me know if there is any problem with this PR. Should I close if it not needed.

[aymeric-roucher]

@keetrap is this fixing any failing tool initialization? Normally, having Any in tool arguments is supported and tested in tests/test_tools.py::test_tool_supports_any_none, tell me if you have a counterexample!

[keetrap]

@aymeric-roucher
Yes, this fix the FinalanswerTool without this code the error is:

ValueError: Tool validation failed:
- forward: Name 'Any' is undefined.

This error only occurs when use_e2b_executor=True

[aymeric-roucher]

Then this is due to calling method Tool.save! Could you add this line in test_tool_supports_any_none (in tests/test_tools.py):
get_weather.save()
This may force you to add None as well to self.typing_names

[keetrap]

I added the line and ran the tests. The error was: TypeError: Tool.save() missing 1 required positional argument: 'output_dir'. After providing the output_dir, the tests passed without adding None to self.typing_names.

[keetrap]

I am still confused as to why there is an error, and this only occurs when use_e2b_executor=True. It is not occurring in the local Python executor because we are not validating the tool attributes there.

Thanks for merging this PR.