pmb: Remove unused imports + Revert "ci/ruff: hardcode version 0.13.2"

Newbyterequested to merge
newbyte/ruff-update into master

As found by Ruff 0.13.3.

This was done because Ruff 0.13.3 found various new issues. These have now been fixed, so let's use the latest version again.

This reverts commit 1c6aca12.

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