clean pylint, mypy, pyright issue for legacy code of autorest.python

[msyyc]

There is still some pylint issue in legacy code of autorest.python folder: #2981 (comment).
We shall remove the disable configuration of pylintrc after fix them.

[iscai-msft]

is this legacy code in the autorest.python code package, or legacy SDKs generated by autorest.python. I'm fine to add pylint checks for legacy code SDKs generated as well

[msyyc]

is this legacy code in the autorest.python code package, or legacy SDKs generated by autorest.python. I'm fine to add pylint checks for legacy code SDKs generated as well

legacy SDKs generated by autorest.python

[iscai-msft]

transferred to microsoft/typespec#5786