🐛 E3V2 Brightness followup (#22821)

Co-authored-by: Scott Lahteine <github@thinkyhead.com>

Marlin/src/lcd/e3v2/creality/dwin.cpp

@@ -1816,6 +1816,10 @@ void HMI_SDCardInit() { card.cdroot(); }
 
 void MarlinUI::refresh() { /* Nothing to see here */ }
 
+#if HAS_LCD_BRIGHTNESS
+  void MarlinUI::_set_brightness() { DWIN_LCD_Brightness(backlight ? brightness : 0); }
+#endif
+
 #if ENABLED(SCROLL_LONG_FILENAMES)
 
   char shift_name[LONG_FILENAME_LENGTH + 1];