[GHA] Update CodeQL workflows

[imnasnainaec]

• Remove CodeQL from the backend workflow, because:
  • it was redundant with what's in the codeql workflow,
  • it had a no-longer-necessary "Setup .NET" step that was a relic of CodeQL previously not supporting the newest .NET,
  • it wasn't even uploading results (e.g., https://github.com/sillsdev/TheCombine/actions/runs/13061541171/job/36446160360#step:9:527);
• Add actions to the languages to analyze, since CodeQL now supports GHA analysis;
• Bump to the latest version, which includes said support.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.45%. Comparing base (1072018) to head (ae2a0c5).
Report is 29 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3563      +/-   ##
==========================================
- Coverage   74.49%   74.45%   -0.05%     
==========================================
  Files         285      285              
  Lines       11007    11007              
  Branches     1333     1333              
==========================================
- Hits         8200     8195       -5     
- Misses       2424     2428       +4     
- Partials      383      384       +1     

Flag	Coverage Δ
backend	83.69% <ø> (-0.10%)	⬇️
frontend	66.30% <ø> (ø)

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[jasonleenaylor]

Reviewed 1 of 2 files at r1, 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @imnasnainaec)