feat(pico-sensor): added callback in mqtt client to process incomming messages in application

pico-sensor/src/application.c

@@ -136,6 +136,10 @@ static void MqttTask(void *pv) {
   } /* for */
 }
 
+static void MyMqttMessageCallback(topic_ID_e topic, const unsigned char *payload, size_t len) {
+  McuLog_info("MQTT message received, topic: %d, payload: %.*s", topic, (int)len, payload);
+}
+
 #endif
 
 void App_Init(void) {
@@ -154,6 +158,7 @@ void App_Init(void) {
   }
 #endif
 #if PL_CONFIG_USE_MQTT_CLIENT
+  MqttClient_RegisterMessageCallback(MyMqttMessageCallback); // register the callback for incoming messages
   if (xTaskCreate(
       MqttTask,  /* pointer to the task */
       "mqtt", /* task name for kernel awareness debugging */