More robust help injection in CLI

[tom21100227]

Currently sleap-nn-train does not take commandline overrides because of a bug with how hydra handles overrides, this PR solves it.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.39%. Comparing base (ff91433) to head (51cec07).
⚠️ Report is 19 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #303      +/-   ##
==========================================
+ Coverage   95.28%   95.39%   +0.10%     
==========================================
  Files          49       49              
  Lines        6765     6990     +225     
==========================================
+ Hits         6446     6668     +222     
- Misses        319      322       +3     

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[tom21100227]

thank you CI tools for sparing my PR

[tom21100227]

This would also close #301 and added test to prevent new additions from breaking it again.