TEMP: add pull_request trigger to verify kernel workflow on PR (revert before merge)

Author: sd-db

.github/workflows/integration-kernel.yml

@@ -21,6 +21,7 @@
 name: Kernel Integration Tests
 on:
   workflow_dispatch:
+  pull_request:  # TEMP: verify the workflow runs on PR #1576; reverted before merge.
   schedule:
     - cron: "17 9 * * 6"  # Weekly: Saturday 09:17 UTC (14:47 IST). Clear of the
                           # daily 21:30 UTC nightly and the Sunday SPOG slot,