fix(ci): checkout the pr head instead of the default main head

[kumvprat]

Issue # (if applicable)

Closes #.

Reason for this change

Fix the invalid revision range issues : https://github.com/aws/aws-cdk/actions/runs/19970012866/job/57272071527

Since the action checks out the main branch HEAD instead of PR branch HEAD : https://github.com/aws/aws-cdk/actions/runs/19970012866/job/57272071527#step:2:1094

Inspired from : https://github.com/aws/aws-cdk/blob/main/.github/workflows/integration-test-deployment.yml#L39C11-L39C57

Description of changes

Describe any new or updated permissions being added

Description of how you validated changes

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[aws-cdk-automation]

(This review is outdated)

[github-actions]

	Tests	Passed ❌️	Skipped	Failed
Security Guardian Results	0 ran	0 passed	0 skipped	0 failed

Test	Result
No test annotations available

• View Security Guardian Results

[github-actions]

	Tests	Passed ❌️	Skipped	Failed
Security Guardian Results with resolved templates	0 ran	0 passed	0 skipped	0 failed

Test	Result
No test annotations available

• View Security Guardian Results with resolved templates

✅ Updated pull request passes all PRLinter validations. Dismissing previous PRLinter review.

[mergify]

Merge Queue Status

✅ The pull request has been merged

This pull request spent 28 minutes 3 seconds in the queue, including 27 minutes 54 seconds running CI.
The checks were run in-place.

Required conditions to merge

• #approved-reviews-by >= 1 [🛡 GitHub branch protection]
  • fix(ci): checkout the pr head instead of the default main head #36311
• #changes-requested-reviews-by = 0 [🛡 GitHub branch protection]
  • fix(ci): checkout the pr head instead of the default main head #36311
• any of [🛡 GitHub branch protection]:
  • check-success = validate-pr
  • check-neutral = validate-pr
  • check-skipped = validate-pr
• any of [🛡 GitHub branch protection]:
  • check-success = build
  • check-neutral = build
  • check-skipped = build

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[github-actions]

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