perf(worker): Batch fetch testruns for flake processing

[sentry]

Fixes WORKER-Y91. The issue was that: Processing flakes for a repository results in an N+1 query, fetching testruns individually for each upload, causing task timeouts.

• Introduced get_testruns_for_uploads to fetch testruns for multiple uploads in a single batched query.
• Grouped fetched testruns by upload ID in memory using defaultdict.
• Modified process_single_upload to accept pre-fetched testruns instead of an upload object.
• Updated process_flakes_for_commit to utilize the new batched fetching mechanism, significantly reducing database queries.

This fix was generated by Seer in Sentry, triggered automatically. 👁️ Run ID: 13566081

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Note

Medium Risk
Moderate risk because it changes the flake-processing query pattern and refactors process_single_upload’s inputs; correctness depends on grouping testruns by upload_id and handling uploads with no testruns.

Overview
Reduces N+1 DB queries in flake processing by batching testrun retrieval across all relevant uploads for a commit.

Replaces per-upload testrun queries with get_testruns_for_uploads(upload_ids) (single upload_id__in query) and updates process_single_upload to accept pre-fetched testruns; process_flakes_for_commit now preloads and groups testruns in-memory via defaultdict before processing each upload.

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[sentry]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.25%. Comparing base (0ad8a0c) to head (53ddcdd).
⚠️ Report is 32 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #867   +/-   ##
=======================================
  Coverage   92.25%   92.25%           
=======================================
  Files        1307     1307           
  Lines       48017    48023    +6     
  Branches     1636     1636           
=======================================
+ Hits        44299    44305    +6     
  Misses       3407     3407           
  Partials      311      311           

Flag	Coverage Δ
workerintegration	58.53% <16.66%> (-0.02%)	⬇️
workerunit	90.39% <100.00%> (+<0.01%)	⬆️

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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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