Hide (or remove) custom character change on boot screen

Marlin/ultralcd_impl_HD44780.h

       safe_delay(2000);
     #endif
 
+    /*
+    lcd.clear();
+
     lcd_set_custom_characters(
       #if ENABLED(LCD_PROGRESS_BAR)
         false
       #endif
     );
+    //*/
   }
 
 #endif // SHOW_BOOTSCREEN