Ensure issues without core labels have triage labels (#19243)

Sometimes, issues are created outside of issue templates (which we don't
prefer, but we can't prevent). This updates our top-ranking issues
script such that it will add `triage` and `admin read` labels to any
issue that is missing a core label, so that we don't miss the issues
when doing the next triage.

Release Notes:

- N/A

script/label_data.json

@@ -9,5 +9,6 @@
     "support"
   ],
   "additional_labels": ["ai", "linux", "vim", "windows"],
-  "ignored_label": "ignore top-ranking issues"
+  "ignored_label": "ignore top-ranking issues",
+  "new_issue_labels": ["triage", "admin read"]
 }