Remove extra delay after critical sound

This delay doesn't exist for the tone generator, so remove it from the
pure version as well.

Firmware/sound.cpp

@@ -84,7 +84,6 @@ void Sound_MakeCustom(uint16_t ms,uint16_t tone_,bool critical){
                WRITE(BEEPER, HIGH);
                _delay(ms);
                WRITE(BEEPER, LOW);
-               _delay(ms);
           }
           else{
                _tone(BEEPER, tone_);