More comprehensive client proxy queue guards (#3414)

* More comprehensive MQTT thread and queue guards

* Consolidate logic

* Remove channel check

* Check for map_reporting_enabled as well

* Update message

* Remove channel check from here as well

* One liner

* Start the mqtt thread back up when channels change and we want mqtt

src/mqtt/MQTT.h

@@ -71,6 +71,10 @@ class MQTT : private concurrency::OSThread
 
     void onClientProxyReceive(meshtastic_MqttClientProxyMessage msg);
 
+    bool isEnabled() { return this->enabled; };
+
+    void start() { setIntervalFromNow(0); };
+
   protected:
     PointerQueue<meshtastic_ServiceEnvelope> mqttQueue;