Ensure Ruff checks formatting during CI checks

[whabanks]

Summary | Résumé

• Updated Ruff to 0.8.2.
• Updated Ruff VScode extension to prevent automatic removal of unused imports on save. Unused imports will still be removed when make format is ran.
• Ruff will now properly check formatting in CI.

Test instructions | Instructions pour tester la modification

1. Dev container builds
2. Open any python file and add an unused import from app import celery for example
3. Save the file
4. Note that the unused import was not removed and that the imports are highlighted indicating a linter error.
5. Run make format
6. Note that the unused import was removed.

Reviewer checklist | Liste de vérification du réviseur

• This PR does not break existing functionality.
• This PR does not violate GCNotify's privacy policies.
• This PR does not raise new security concerns. Refer to our GC Notify Risk Register document on our Google drive.
• This PR does not significantly alter performance.
• Additional required documentation resulting of these changes is covered (such as the README, setup instructions, a related ADR or the technical documentation).

⚠ If boxes cannot be checked off before merging the PR, they should be moved to the "Release Instructions" section with appropriate steps required to verify before release. For example, changes to celery code may require tests on staging to verify that performance has not been affected.