fix(worker): Optimize N+1 queries in ProcessFlakesTask

[sentry]

This PR addresses an N+1 query pattern identified in the app.tasks.flakes.ProcessFlakesTask, specifically within the services.test_analytics.ta_process_flakes module.

Problem:
Previously, process_flakes_for_commit would iterate through each ReportSession (upload) and then call get_testruns(upload), which executed a separate database query to fetch testruns for that specific upload. This resulted in N+1 queries, where N is the number of uploads for a given commit.
Additionally, when a flake expired (reached 30 recent passes), handle_pass would call flake.save() individually, leading to further N+1 queries if many flakes expired in a single run.

Solution:

1. Batch Testrun Fetching: Introduced get_testruns_for_uploads to fetch all relevant Testrun objects for all uploads associated with a commit in a single batched query. The process_single_upload function was updated to receive these pre-fetched testruns, eliminating the per-upload database calls.
2. Bulk Update for Expired Flakes: Modified handle_pass to no longer call flake.save() directly. Instead, expired Flake objects are collected into a list (expired_flakes), and a single Flake.objects.bulk_update() is performed at the end of process_flakes_for_commit to persist these changes efficiently.

These changes significantly reduce the database load and improve the performance of the ProcessFlakesTask by converting multiple individual queries into batched operations.

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Fixes WORKER-YVA

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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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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.89%. Comparing base (e682d07) to head (25de8a6).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1240      +/-   ##
==========================================
- Coverage   91.89%   91.89%   -0.01%     
==========================================
  Files        1325     1325              
  Lines       50868    50878      +10     
  Branches     1626     1626              
==========================================
+ Hits        46744    46752       +8     
- Misses       3818     3820       +2     
  Partials      306      306              

Flag	Coverage Δ
workerintegration	58.53% <12.50%> (-0.04%)	⬇️
workerunit	90.36% <100.00%> (-0.01%)	⬇️

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