style: fix more linting/ruff issues in tests

[aucampia]

Summary of changes

This eliminates the need for all file level ignores in pyproject.toml

Checklist

• Checked that there aren't other open pull requests for
  the same change.
• Checked that all tests and type checking passes.
• Considered granting push permissions to the PR branch,
  so maintainers can fix minor issues and keep your PR up to date.

[coveralls]

coverage: 90.94%. remained the same when pulling 8d896d6 on aucampia:aucampia/20230831T2304-more-linting-fixes-tests into 8ee2d2f on RDFLib:main.