Coding Standards: Remove extra `unset()` in `rest_handle_options_requ… #19424

Job	Run time
Performance tests / Run tests	9m 52s
Performance tests (with memcached) / Run tests	9m 52s
Slack Notifications / Prepare notifications	8s
Slack Notifications / Success notifications	3s
Slack Notifications / Failure notifications	0s
Slack Notifications / Fixed notifications	0s
Slack Notifications / Cancelled notifications	0s
Failed workflow tasks	0s
	19m 55s

Provide feedback