MCU8MASS-1943 Don't send AT commands for MQTT disconnect if the modem is not connected to the network

Author: M65649

src/mqtt_client.cpp

@@ -541,14 +541,14 @@ bool MqttClientClass::end(void) {
     SequansController.unregisterCallback(MQTT_ON_CONNECT_URC);
     SequansController.unregisterCallback(MQTT_ON_DISCONNECT_URC);
 
-    if (isConnected()) {
+    if (Lte.isConnected() && isConnected()) {
 
         SequansController.writeCommand(MQTT_DISCONNECT);
         SequansController.clearReceiveBuffer();
-
-        connected_to_broker = false;
     }
 
+    connected_to_broker = false;
+
     if (disconnected_callback != NULL) {
         disconnected_callback();
     }