Bug Fix after MQTT Transport connection statistics

common/transport/mqtt/src/main/java/org/thingsboard/server/transport/mqtt/MqttTransportContext.java

@@ -77,6 +77,7 @@ public class MqttTransportContext extends TransportContext {
 
     @PostConstruct
     public void init() {
+        super.init();
         transportService.createGaugeStats("openConnections", connectionsCounter);
     }