ci: wait for a newer run instead of failing on an earlier one's result

.github/workflows/core-checks.yml

@@ -6,6 +6,15 @@ name: Core Checks
 
 on:
   pull_request:
+    # The same activity types as the Required Merge Gate, which waits for
+    # its own event's Core Checks Gate instead of an earlier event's failure.
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - ready_for_review
+      - labeled
+      - unlabeled
     branches:
       - main
       - 1.0.0