Could probably be causing issues, onClock shouldn’t have anything in its parenthesis and if you delete that it’ll clear up the error.
Code:
 void onClock(byte channel, byte note, byte velocity) {
  if (!bankSelect){
    if (ClockCount<=3){
      digitalWrite(MODE_TAP_LED_PIN, LED_ON);
    }else{
      digitalWrite(MODE_TAP_LED_PIN, LED_OFF);
    }
  }
  ++ClockCount = ClockCount%24;
}