fix(worker): eliminate N+1 query in ProcessFlakesTask

[sentry]

This PR addresses an N+1 query issue in app.tasks.flakes.ProcessFlakesTask, specifically within the process_flakes_for_commit function in apps/worker/services/test_analytics/ta_process_flakes.py.

Problem:
Previously, when process_flakes_for_commit was executed for a commit that had multiple associated uploads, it would iterate through each upload and call process_single_upload for each one. Each call to process_single_upload would then perform a separate SELECT query to fetch testruns and a separate bulk_update to modify their outcomes. This led to an N+1 query pattern, where N is the number of uploads for a given commit, resulting in N SELECTs and N UPDATEs on the ta_timeseries_testrun table.

Solution:
To resolve this, the logic has been refactored to batch these database operations:

1. A new function, get_testruns_for_uploads, was introduced to fetch all relevant testruns for all uploads associated with a commit in a single SELECT query using upload_id__in.
2. A new function, process_all_uploads, was created to process all these fetched testruns in a single pass, applying the flake detection logic.
3. The process_flakes_for_commit function now calls process_all_uploads once, which then performs a single bulk_update on all modified testruns.

This change reduces the database interactions from N SELECTs + N UPDATEs to a single SELECT + a single UPDATE, significantly improving performance for commits with multiple uploads.

Legal Boilerplate

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Fixes WORKER-YV1

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.86%. Comparing base (e682d07) to head (fa19945).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1231      +/-   ##
==========================================
- Coverage   91.89%   91.86%   -0.03%     
==========================================
  Files        1325     1325              
  Lines       50868    50884      +16     
  Branches     1626     1626              
==========================================
+ Hits        46744    46745       +1     
- Misses       3818     3833      +15     
  Partials      306      306              

Flag	Coverage Δ
workerintegration	58.52% <15.78%> (-0.04%)	⬇️
workerunit	90.29% <100.00%> (-0.09%)	⬇️

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Codecov Report

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

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