chore(fill): delete output directory if no tests were ran

[danceratopz]

🗒️ Description

A suggestion to:

• bug(fill): fill generates a .meta directory even if no tests executed #1613

Respectively alternative to:

• chores(src): nuke fixtures dir when html is disabled and no tests were filled #2014

This:

• Uses a hook wrapper to make sure that we delete the directory after the pytest-html plugin has written its html output.
• Filters out the pytest-html "Generated html report:" line from the summary to avoid confusion.

The whole thing is hacky, but it's a better solution than #2014 imo:

• The logic in pytest_terminal_summary is worse/more complex.
• The logic in ptyest_sessionfinish is slightly better.

If we want to be less hacky, then the other option is to stop generating html by default.

🔗 Related Issues or PRs

N/A.

✅ Checklist

• All: Ran fast tox checks to avoid unnecessary CI fails, see also Code Standards and Enabling Pre-commit Checks:

  uvx --with=tox-uv tox -e lint,typecheck,spellcheck,markdownlint

• All: PR title adheres to the repo standard - it will be used as the squash commit message and should start type(scope):.
• All: Considered adding an entry to CHANGELOG.md.
• All: Considered updating the online docs in the ./docs/ directory.
• All: Set appropriate labels for the changes (only maintainers can apply labels).