fix: fall back TopK whose later sort key can fail under ANSI - #7457

CI run on tlfua/datafusion-comet for 37be546.

Rerun failed checks in the fork. A green fork run tests the branch head, not its merge with main.

This check is informational: the contributor controls the fork workflow. The upstream merge queue runs the required CI checks on the proposed merge result. Active or missing runs on recently updated PRs are polled every 15 minutes; a rotating sweep also discovers reruns on older PRs. Scheduled updates may be delayed.