additional_skip_names are not respected everywhere in pathlib

[sassanh]

Describe the bug

Path().exists and Path().unlink for example don't work well with additional_skip_names.

Context: https://github.com/pytest-dev/pyfakefs/issues/1021#issuecomment-2132637499

The current implementation is incomplete (yes, actually all methods should respect additional_skip_names) and ugly (using the callstack). I had hoped that it will sufficient until I get back to it, but obviously I was wrong.