chore: Define Auth type alias in types module

[edgarrmondragon]

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📚 Documentation preview 📚: https://meltano-sdk--2586.org.readthedocs.build/en/2586/

[codspeed-hq]

CodSpeed Performance Report

Merging #2586 will not alter performance

_{Comparing edgarrmondragon/chore/auth-type-alias (a45b0cb) with main (a4a3561)}

Summary

✅ 6 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.47%. Comparing base (a4a3561) to head (a45b0cb).
Report is 121 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2586      +/-   ##
==========================================
- Coverage   89.47%   89.47%   -0.01%     
==========================================
  Files          58       58              
  Lines        4799     4798       -1     
  Branches      936      936              
==========================================
- Hits         4294     4293       -1     
  Misses        352      352              
  Partials      153      153              

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