Remove redundant MQTT subscribe

include/wlan.h

@@ -20,8 +20,6 @@ void connect_mqtt();
 
 void wlan_connection_handler(WiFiEvent_t event);
 
-void on_mqtt_connection(bool session);
-
 void on_mqtt_disconnection(AsyncMqttClientDisconnectReason reason);
 
 size_t construct_json(float *data, char *buffer, int buffer_size);

src/wlan.cpp

@@ -3,7 +3,6 @@
 void initialize_wlan() { WiFi.onEvent(wlan_connection_handler); }
 
 void initialize_mqtt() {
-    mqtt_client.onConnect(on_mqtt_connection);
     mqtt_client.onDisconnect(on_mqtt_disconnection);
     mqtt_client.setServer(config->mqtt_host, config->mqtt_port);
     mqtt_client.setCredentials(config->mqtt_user, config->mqtt_password);
@@ -32,11 +31,6 @@ 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_disconnection(AsyncMqttClientDisconnectReason reason) {
     Serial.println("MQTT disconnected");