fix missing MultipleObjectsReturnedException for FormsService

Signed-off-by: Timotheus Pokorra <[email protected]>

lib/Service/FormsService.php

@@ -21,6 +21,7 @@
 use OCA\Forms\Events\FormSubmittedEvent;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\AppFramework\Db\IMapperException;
+use OCP\AppFramework\Db\MultipleObjectsReturnedException;
 use OCP\EventDispatcher\IEventDispatcher;
 use OCP\Files\IRootFolder;
 use OCP\Files\NotFoundException;