Add regime in spectrum duplicate check in find_spectra

[ying2212]

The find_spectra() function includes source, mode, observation_date, and reference but regime is not used in the duplicate check when ingesting spectra.
This PR update adds regime to prevent ingesting spectra that are identical in all fields except regime.

[kelle]

Please try to add a test which tests this new functionality.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.38%. Comparing base (de048fd) to head (c8da5ab).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #236      +/-   ##
==========================================
+ Coverage   71.32%   72.38%   +1.06%     
==========================================
  Files          19       19              
  Lines        1653     1673      +20     
  Branches      210      211       +1     
==========================================
+ Hits         1179     1211      +32     
+ Misses        387      380       -7     
+ Partials       87       82       -5     

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[kelle]

(Notice that the code coverage report is also not happy because the new code isn't being tested.)

[ying2212]

Added test coverage to verify the regime duplicate check in find_spectra and ingest_spectrum
This ensure two spectra with identical keys but different regimes can both be ingested, and that a true duplicate (including the same regime) is correctly rejected.

[kelle]

Minor tweak to docstring. otherwise, looks great! (Assuming tests pass.)