TYP: make numpy.typing available from pandas._typing
xref https://github.com/pandas-dev/pandas/issues/41807#issuecomment-859372500

this does not update the `__array__` to `to_numpy` methods of EA, see https://github.com/pandas-dev/pandas/pull/41185#issuecomment-852469918 but does need a couple of ignores till that is done.

(we are removing 3 anyway, so a net reduction in ignores :smile:, and reducing false positives for users)


does this require 1.21? (though passing for all so guess is no) for runtime, `npt: Any = None` means that the numpy version is not relevant. For type checking, `import numpy.typing as npt` so needs at least 1.20, but would not be checking without 1.21 anyway otherwise will get other errors. thanks @simonjayhawkins 