Disallow StringMethods for Series and Index when subtype is not `str`, but allow for `Any`

[Dr-Irv]

In #1146 tried to get StringMethods to know that passing Series[float] (for example) is wrong.

I got something to work for Series with pyright . See https://github.com/Dr-Irv/pandas-stubs/tree/pr1146 and this commit: 164bc27

Would like to add this to the stubs.

But as noted here: #1146 (comment) it fails in mypy which seems to be due to python/mypy#15921