skip trigger for review bot on draft PRs (#2145)

Added if condition on review-bot's trigger so it does not trigger in
`draft` PRs.

.github/workflows/review-trigger.yml

@@ -13,6 +13,7 @@ on:
 
 jobs:
   trigger-review-bot:
+    if: github.event.pull_request.draft != true
     runs-on: ubuntu-latest
     name: trigger review bot
     steps: