Fix LPC176x RGB NEOPIXEL startup (#18380)

Marlin/src/feature/leds/neopixel.cpp

 }
 
 void Marlin_NeoPixel::init() {
-  SET_OUTPUT(NEOPIXEL_PIN);
   set_brightness(NEOPIXEL_BRIGHTNESS); // 0 - 255 range
   begin();
   show();  // initialize to all off
 
   #if ENABLED(NEOPIXEL_STARTUP_TEST)
-    safe_delay(1000);
     set_color_startup(adaneo1.Color(255, 0, 0, 0));  // red
     safe_delay(1000);
     set_color_startup(adaneo1.Color(0, 255, 0, 0));  // green