PR path-labeler can remove labels added by concurrent workflows

Describe the Issue

1. Two workflows can update a pull request's labels at the same time:

   GitHub - PR Contribution Guidelines adds deprioritized when a contribution-guideline check fails.

   GitHub - Label PRs independently calculates path-based labels with sync-labels: true.

   The path-labeler action reads the existing labels and later replaces the complete label set. A label added by another workflow between those operations can be omitted from the replacement set.

2. This occurred on pull request #70509. The contribution-guidelines workflow added deprioritized after detecting a commit made through the GitHub web editor. One second later, the concurrently running path-labeler workflow removed deprioritized while adding scope: curriculum. The failed guideline condition remained unresolved when the label disappeared.

Affected Pages

• https://github.com/freeCodeCamp/freeCodeCamp/blob/ff001b767cc6a0d2e0ff04c0598c36451b035edc/.github/workflows/github-pr-guidelines.yml
• https://github.com/freeCodeCamp/freeCodeCamp/blob/ff001b767cc6a0d2e0ff04c0598c36451b035edc/.github/workflows/github-labeler.yaml
• https://github.com/freeCodeCamp/freeCodeCamp/pull/70509
• https://github.com/freeCodeCamp/freeCodeCamp/actions/runs/36669688239
• https://github.com/freeCodeCamp/freeCodeCamp/actions/runs/36669688257

Expected behavior

Labels added by contribution-guideline checks should remain on a pull request until the corresponding condition is resolved. Path-based label updates should not remove labels added concurrently by another workflow.