fix(dav): Add missing use for OCP\Constants

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

Author: come-nc

apps/dav/lib/SystemTag/SystemTagsRelationsCollection.php

@@ -26,6 +26,7 @@
  */
 namespace OCA\DAV\SystemTag;
 
+use OCP\Constants;
 use OCP\IGroupManager;
 use OCP\IUserSession;
 use OCP\SystemTag\ISystemTagManager;