feat: remove flake detection feature flags

[joseph-sentry]

this also fixes a test that was previously not working correctly

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: services/test_results.py

Function	Unhandled Issue
should_do_flaky_detection	Plan.DoesNotExist: Plan matching query does not exist. app.tasks.test_results.TestResultsFinish... Event Count: 188
should_do_flaky_detection	Plan.DoesNotExist: Plan matching query does not exist. app.tasks.pull... Event Count: 38

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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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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.25%. Comparing base (d7b53d8) to head (3eab684).
Report is 2 commits behind head on main.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1102      +/-   ##
==========================================
- Coverage   97.28%   97.25%   -0.03%     
==========================================
  Files         454      454              
  Lines       37355    37327      -28     
==========================================
- Hits        36339    36302      -37     
- Misses       1016     1025       +9     

Flag	Coverage Δ
integration	43.12% <83.33%> (-0.03%)	⬇️
unit	89.79% <50.00%> (+0.01%)	⬆️

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