fix agent name calculation for gradio app

[sysradium]

Fixes this issue:

Traceback (most recent call last):
  File "/Users/user/Documents/Dev/sysradium/ml-playground/agents/smol_example.py", line 163, in <module>
    demo = GradioUI(agent).create_app()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/user/Documents/Dev/sysradium/ml-playground/.venv/lib/python3.12/site-packages/smolagents/gradio_ui.py", line 270, in create_app
    f"# {self.name.replace('_', ' ').capitalize() or 'Agent interface'}"

Name is optional and thus by default is None:

smolagents/src/smolagents/agents.py

Line 214 in af03d17

self.name = name

Also if name is not event specified it is None as well:
https://github.com/huggingface/smolagents/blob/main/src/smolagents/gradio_ui.py#L187
Hence the bugfix.

Maybe we can consider using this instead:
https://github.com/huggingface/smolagents/blob/main/src/smolagents/agents.py#L205

[aymeric-roucher]

Thanks @sysradium !

[aymeric-roucher]

Make sure to run ruff formatting @sysradium !

[sysradium]

@aymeric-roucher it complaints about a file which is not changed ... Weird. I rebased. I ran formatting locally just in case.