fix(api): Remove BasicAuthentication to prevent AttributeError

[sentry]

This PR addresses issue API-9W4, where WrappedAttributeError: 'Manager' object has no attribute 'get_by_natural_key' was occurring on badge endpoints.

The error was triggered when requests to these endpoints included HTTP Basic Authentication headers. Django Rest Framework's BasicAuthentication class, which was enabled by default, would attempt to authenticate these requests by calling get_by_natural_key() on Codecov's custom User model manager. However, our custom User model manager does not implement this method, leading to the AttributeError.

Since Codecov does not utilize Basic Authentication (relying instead on Token and Session authentication), the rest_framework.authentication.BasicAuthentication class is unnecessary. This change removes it from the DEFAULT_AUTHENTICATION_CLASSES tuple in apps/codecov-api/codecov/settings_base.py, thereby eliminating the code path that caused the error.

Legal Boilerplate

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Fixes API-9W4

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.83%. Comparing base (d8942db) to head (98043fa).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1883   +/-   ##
=======================================
  Coverage   91.83%   91.83%           
=======================================
  Files        1332     1332           
  Lines       51830    51830           
  Branches     1647     1647           
=======================================
  Hits        47598    47598           
  Misses       3911     3911           
  Partials      321      321           

Flag	Coverage Δ
apiunit	94.75% <ø> (ø)

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[codecov-notifications]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

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