ai: apply changes for #879 (1 review thread)

Addresses:
  - #3641618444 at .github/workflows/trigger-integration-tests.yml:459

Signed-off-by: peco-engineer-bot[bot] <peco-engineer-bot[bot]@users.noreply.github.com>

Author: peco-engineer-bot[bot]

.github/workflows/trigger-integration-tests.yml

@@ -462,7 +462,8 @@ jobs:
     if: |
       github.event_name == 'pull_request' &&
       github.event.action == 'closed' &&
-      github.event.pull_request.merged == true
+      github.event.pull_request.merged == true &&
+      github.event.pull_request.base.ref == 'main'
     runs-on:
       group: databricks-protected-runner-group
       labels: linux-ubuntu-latest