fix issue - station config not wait

EVCB_OCPP.WSServer/Service/StationConfigService.cs

@@ -109,6 +109,7 @@ public class StationConfigService
                 modifiedStations.Contains(sessionStationId.Value))
             {
                 var tmp = UpdateEvseConfig(evse.ChargeBoxId, sessionStationId.Value);
+                updateTasks.Add(tmp);
             }
         }
         await Task.WhenAll(updateTasks);