add LastActiveTime on startup

EVCB_OCPP.WSServer/Service/WsService/WsSession.cs

@@ -46,6 +46,7 @@ public class WsSession
     private void Init(WebSocket webSocket)
     {
         _WebSocket = webSocket;
+        LastActiveTime = DateTime.UtcNow;
         ReceiveLoopTask = StartReceivd(webSocket, disconnectCancellationTokenSource.Token);
     }