Check empty ID before releasing lock in Order Storage

The fix from https://www.drupal.org/project/commerce/issues/3468783 📌 Order Storage Lock Release Fixed triggers a fatal error if the order doesn't save properly and doesn't receive an ID beforehand. For example I got it while having faulty code in a presave subscriber.

Previously we were checking isset($this->updateLocks[$entity->id()]) so maybe let's add back a !empty($entity->id())? Not sure if the lock would still persist is some other edge cases.