feat(ci): cancel in-progress PR workflows on new commit push

[joshuarli]

this adds concurrency cancellation to pull_request workflows so that pushing a new commit to a PR automatically cancels any still-running workflow from the previous commit

99% of the time if you push a new commit you don't care about the previous workflow if its still running

we already do this for all sentry+getsentry pull_request workflows

we (devinfra) can't measure this yet but this would greatly help decrease org-wide runner queue pressure!

[github-actions]

Semver Impact of This PR

🟡 Minor (new features)

📋 Changelog Preview

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New Features ✨

• (ci) Cancel in-progress PR workflows on new commit push by joshuarli in #5994

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_{🤖 This preview updates automatically when you update the PR.}

[github-actions]

Codecov Results 📊

✅ 13 passed | Total: 13 | Pass Rate: 100% | Execution Time: 9.33s

📊 Comparison with Base Branch

Metric	Change
Total Tests	—
Passed Tests	—
Failed Tests	—
Skipped Tests	—

✨ No test changes detected

All tests are passing successfully.

✅ Patch coverage is 100.00%. Project has 14966 uncovered lines.
✅ Project coverage is 29.7%. Comparing base (base) to head (head).

Coverage diff

@@            Coverage Diff             @@
##          main       #PR       +/-##
==========================================
+ Coverage    24.95%    29.70%    +4.75%
==========================================
  Files          191       191         —
  Lines        21290     21290         —
  Branches      7010      7010         —
==========================================
+ Hits          5311      6324     +1013
- Misses       15979     14966     -1013
- Partials       432       477       +45

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Generated by Codecov Action

[sentrivana]

Let's do it -- we're already doing it in other workflows, too.