Fix token related error while adding PR comment

https://github.com/splunk/public-o11y-docs/actions/runs/15490506134
- add label on PR from forked repositories branches
- add comment on PR from splunk/public-o11y-docs branch

Author: pjurczak-splunk

.github/workflows/heretto-reminder.yml

@@ -17,7 +17,20 @@ jobs:
 
 
     steps:
+      - name: Add PR label
+        if: ${{ github.event.pull_request.head.repo.full_name != github.repository }}
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            github.rest.issues.addLabels({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              labels: ['heretto']
+            })
       - name: Add PR Comment
+        if: ${{ github.head_ref == 'repo-sync' }}
         uses: actions/github-script@v6
         with:
           github-token: ${{ secrets.MY_TOKEN }}