Provide more accurate link for Repo Sync PRs (#17145)

Co-authored-by: chiedo <chiedo@users.noreply.github.com>

Author: chiedo

.github/workflows/repo-sync-stalls.yml

@@ -58,4 +58,4 @@ jobs:
           channel: ${{ secrets.DOCS_ALERTS_SLACK_CHANNEL_ID }}
           bot-token: ${{ secrets.SLACK_DOCS_BOT_TOKEN }}
           color: failure
-          text: Repo sync appears to be stalled for ${{github.repository}}. See https://github.com/${{github.repository}}/pulls?q=is%3Apr+is%3Aopen+repo+sync
+          text: Repo sync appears to be stalled for ${{github.repository}}. See https://github.com/${{github.repository}}/pulls?q=is%3Apr+is%3Aopen+label%3Aautomated-reposync-pr