Restore support for pathlib paths in build_base

[jaraco]

• In sdist.prune_file_list, support build.build_base as a pathlib.Path.
• Add test capturing missed expectation.
• Enable the test
• Add news fragment.

Merges incidental changes in distutils:

• Use monkeypatch to monkeypatch.
• Disable TRY400 so it doesn't cause problems in other branches. Disable RUF100 to prevent it from failing in this branch. Ref Unexpected TRY400 indicated in unchanged code distutils#292

Summary of changes

Closes #4615

Pull Request Checklist

• Changes have tests
• News fragment added in newsfragments/.
  (See documentation for details)

[abravalheri]

Thank you very much Jason!

[jaraco]

These tests passed on pypy here, but failed on the release job (https://github.com/pypa/setuptools/actions/runs/10692324985).