Use regular groups endpoint to support Nextcloud 13

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Controller/ConfigController.php

@@ -106,10 +106,6 @@ class ConfigController extends Controller {
 			return [
 				'id' => $group->getGID(),
 				'displayname' => $group->getDisplayName(),
-				'usercount' => $group->count(),
-				'disabled' => $group->countDisabled(),
-				'canAdd' => $group->canAddUser(),
-				'canRemove' => $group->canRemoveUser(),
 			];
 		}, $groups);
 		return $groups;