When attempting to import a user without a requestPreference, mod-user-import will attempt to DELETE existing request preferences even if updateOnlyPresentFields is set to true.
1. Create a user manually with preferences so that the request preferences entry is created.
2. Fire off an import containing info about that user. Eg,
3. Note the response contains a failedUsers entry. Eg,
Now, obviously there shouldn't be an error if we are trying to delete the request preference. That's bug #1. But bug #2 is that the code should definitely not unconditionally attempt to delete the request preference if it's nullish, as it does here. It should be checking the value of updateOnlyPresentFields.