Improve UART test reliability

Author: nseidle

Firmware/RTK_Surveyor/Display.ino

@@ -1451,6 +1451,13 @@ void paintSystemTest()
     //Verify the ESP UART2 can communicate TX/RX to ZED UART1
     if (zedUartPassed == false)
     {
+      setMuxport(MUX_UBLOX_NMEA); //Set mux to UART so we can debug over data port
+      delay(20);
+
+      //Clear out buffer before starting
+      while(serialGNSS.available()) serialGNSS.read();
+      serialGNSS.flush();
+
       SFE_UBLOX_GNSS myGNSS;
 
       //begin() attempts 3 connections

Firmware/RTK_Surveyor/RTK_Surveyor.ino

@@ -362,14 +362,14 @@ void setup()
   Wire.begin(); //Start I2C on core 1
   Wire.setClock(400000);
 
-  beginGNSS(); //Connect to GNSS
+  beginGNSS(); //Connect to GNSS to get module type
 
-  beginEEPROM(); //Start EEPROM and SD for settings
+  beginEEPROM(); //Start EEPROM for settings
   //eepromErase(); //Must be before first use of EEPROM. Currently in beginBoard().
 
-  beginBoard(); //Determine what hardware platform we are running on
+  beginBoard(); //Determine what hardware platform we are running on and check on button
 
-  beginDisplay(); //Check if an external Qwiic OLED is attached
+  beginDisplay(); //Start display first to be able to display any errors
 
   beginLEDs(); //LED and PWM setup