GeezerVison

Backport of #27249 to release/v7.6.7

Triggered by Aditya Patwardhan (@adityapatwardhan) on behalf of @app/dependabot

Original CL Label: CL-BuildPackaging

/cc @PowerShell/powershell-maintainers

Impact

REQUIRED: Choose either Tooling Impact or Customer Impact (or both). At least one checkbox must be selected.

Tooling Impact

• Required tooling change
• Optional tooling change (include reasoning)

Updates the release branch label-validation workflow from actions/github-script v8.0.0 to v9.0.0 so release-branch automation uses the approved dependency version.

Customer Impact

• Customer reported
• Found internally

Regression

REQUIRED: Check exactly one box.

• Yes
• No

This is not a regression.

Testing

Cherry-pick completed without conflicts. Verified the changed workflow file at backport HEAD is byte-for-byte identical to the file at the original merge commit, confirmed there are no conflict markers, and git diff --check HEAD^ HEAD passed. The commit changes only the pinned actions/github-script SHA/version in .github/workflows/labels.yml; CI will provide final workflow validation. An actionlint invocation returned no exit code or output from the Worktree MCP command tool, so no actionlint result is claimed.

Risk

REQUIRED: Check exactly one box.

• High
• Medium
• Low

High risk under the repository guidance because this changes a GitHub Actions workflow dependency used for PR label validation. The backport is narrowly scoped to one pinned action update, is identical to the original merged change, and has no conflict or whitespace errors.