Remove redundant MQTT subscribe

src/wlan.cpp

@@ -32,10 +32,7 @@ void wlan_connection_handler(WiFiEvent_t event) {
     }
 }
 
-void on_mqtt_connection(bool session) {
-    Serial.println("MQTT connected");
-    mqtt_client.subscribe(config->topic, 2);
-};
+void on_mqtt_connection(bool session) { Serial.println("MQTT connected"); };
 
 void on_mqtt_disconnection(AsyncMqttClientDisconnectReason reason) {
     Serial.println("MQTT disconnected");