fix: Fix adding or removing permissions without call permissions set

When adding or removing call permissions the default room permissions
should be taken as a base if no call permission is set. Otherwise adding
will cause the permissions to be set instead of added, while removing
them will have no effect.

Signed-off-by: Daniel Calviño Sánchez <danxuliu@gmail.com>

lib/Service/RoomService.php

@@ -180,6 +180,12 @@ public function setPermissions(Room $room, string $level, string $method, int $p
 		} elseif ($level === 'call') {
 			$property = ARoomModifiedEvent::PROPERTY_CALL_PERMISSIONS;
 			$oldPermissions = $room->getCallPermissions();
+
+			if ($oldPermissions === Attendee::PERMISSIONS_DEFAULT
+					&& ($method === Attendee::PERMISSIONS_MODIFY_ADD
+						|| $method === Attendee::PERMISSIONS_MODIFY_REMOVE)) {
+				$oldPermissions = $room->getDefaultPermissions();
+			}
 		} else {
 			return false;
 		}