✨ DOGM Display Sleep (#23992)

Co-authored-by: borland1 <barryorlando@hotmail.com>

Marlin/src/lcd/dogm/marlinui_DOGM.cpp

@@ -342,6 +342,11 @@ void MarlinUI::draw_kill_screen() {
 
 void MarlinUI::clear_lcd() { } // Automatically cleared by Picture Loop
 
+#if HAS_DISPLAY_SLEEP
+  void MarlinUI::sleep_on()  { u8g.sleepOn(); }
+  void MarlinUI::sleep_off() { u8g.sleepOff(); }
+#endif
+
 #if HAS_LCD_BRIGHTNESS
 
   void MarlinUI::_set_brightness() {