[python] Do not pydantic-validate function args twice

[robertschweizer]

refactor: Use newlines in _with_http_info call
fix: Do not pydantic-validate function args twice

Closes #15757

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@wing328 @multani

[multani]

@robertschweizer Just checking this now (sorry for the delay!)

It seems the status of .raw_function is not really clear in Pydantic v2: according to the documentation, it's not there supported anymore, although it's still there and seems to work as expected.

Also, mypy doesn't really like when this attribute is used.

I'll try to think about something else, if we split the body of the functions as i proposed in #16788 , maybe that can offer an alternative that could also be useful to you, while keeping mypy happy :)

[robertschweizer]

Good catch @multani! I wasn't aware that .raw_function is deprecated/supposed to be removed in pydantic v2. It looks a bit like pydantic devs changed their minds or forgot about removing the field after they wrote the migration guide.

Feel free to revert if this turns out to be a problem. It is just nice-to-have in the end.