fix: remove externally deleted notes from recent notes

[ZebraVogel94349]

This fixes #1603 by checking which files in recentNotes are for non-existent files and removing them, before the list of recent files is returned. Externally deleted files will no longer show up in recent notes.

I've modified the test for getRecentlyAccessed() to test the removal of entries of externally deleted files.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 52.41%. Comparing base (cbc496a) to head (6657b53).
⚠️ Report is 50 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1631      +/-   ##
==========================================
- Coverage   52.62%   52.41%   -0.21%     
==========================================
  Files         133      132       -1     
  Lines        9554     9531      -23     
==========================================
- Hits         5028     4996      -32     
- Misses       4526     4535       +9     

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[adil192]

Thank you!