Update PointPerfect Example18 - correct the topic for the IP dynamic keys

examples/ZED-F9P/Example18_PointPerfectClient/Example18_PointPerfectClient.ino

@@ -36,6 +36,7 @@
   If you don't have a platform with a Qwiic connection use the SparkFun Qwiic Breadboard Jumper (https://www.sparkfun.com/products/14425)
   Open the serial monitor at 115200 baud to see the output
 */
+
 #include <WiFi.h>
 #include <WiFiClientSecure.h>
 #include <ArduinoMqttClient.h> // Click here to get the library: http://librarymanager/All#ArduinoMqttClient
@@ -67,8 +68,11 @@ void setup()
   Serial.println(F("u-blox module connected"));
   myGNSS.setI2COutput(COM_TYPE_UBX); //Turn off NMEA noise
   myGNSS.setPortInput(COM_PORT_I2C, COM_TYPE_UBX | COM_TYPE_NMEA | COM_TYPE_SPARTN); // Be sure SPARTN input is enabled.
-   
+
+  myGNSS.setDGNSSConfiguration(SFE_UBLOX_DGNSS_MODE_FIXED); // Set the differential mode - ambiguities are fixed whenever possible
   myGNSS.setNavigationFrequency(1); //Set output in Hz.
+  myGNSS.setVal8(UBLOX_CFG_SPARTN_USE_SOURCE, 0); // use IP source (default)
+  
   Serial.print(F("Connecting to local WiFi"));
   WiFi.begin(ssid, password);
   while (WiFi.status() != WL_CONNECTED) {
@@ -151,7 +155,7 @@ void beginClient()
         // Subscribe to MQTT and register a callback
         Serial.println(F("Subscribe to Topics")); 
         mqttClient.onMessage(mqttMessageHandler);
-        mqttClient.subscribe(MQTT_TOPIC_KEY);
+        //mqttClient.subscribe(MQTT_TOPIC_KEY); // The ZED does not need the keys in this example. SPARTN is delivered via secure MQTT
         mqttClient.subscribe(MQTT_TOPIC_SPARTN);
         lastReceived_ms = millis();
       } //End attempt to connect