[CI] Try to trigger workflow to block paths on PRs created by github actions and comments (#12688)

Update check-blocked paths GitHub Action workflow to add a
mechanism to trigger this workflow in pull requests created
by other GitHub Actions.

Author: mrodm

Diff for: .github/workflows/block-paths.yml

@@ -3,11 +3,12 @@ name: Block Changes
 on:
   pull_request:
     types: [opened, synchronize, reopened]
-  check_suite:
-    types: [completed]
+  issue_comment:
+    types: [created]
 
 jobs:
   check-blocked-paths:
+    if: ${{ github.event_name == 'pull_request' || (github.event_name == 'issue_comment' && github.event.issue.pull_request && github.event.comment.body == '/check-blocked-paths') }}
     name: Check for blocked path changes
     runs-on: ubuntu-latest
     steps: