test: Use t.Context() instead of context.Background()

[alexandear]

This PR replaces context.Background() with t.Context() in tests. T.Context has been available since Go 1.24.

Additionally, it enables the usetesting linter to automatically suggest using t.Context() in future PRs.

The PR also modifies the helper function createRandomTestRepository by adding a *testing.T parameter. This simplifies integration tests that rely on this function.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.11%. Comparing base (b7f068f) to head (64801d6).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3750   +/-   ##
=======================================
  Coverage   91.11%   91.11%           
=======================================
  Files         187      187           
  Lines       16702    16702           
=======================================
  Hits        15218    15218           
  Misses       1296     1296           
  Partials      188      188           

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[gmlewis]

Thank you, @alexandear!
LGTM.
Awaiting second LGTM+Approval from any other contributor to this repo before merging.

cc: @stevehipwell

[zyfy29]

LGTM

[gmlewis]

Thank you, @zyfy29!
Merging.