Fix and improve FYSETC LCD support (#13767)

Marlin/src/lcd/ultralcd.cpp

@@ -668,6 +668,7 @@ void MarlinUI::update() {
 
   static uint16_t max_display_update_time = 0;
   static millis_t next_lcd_update_ms;
+  millis_t ms = millis();
 
   #if HAS_LCD_MENU
 
@@ -729,11 +730,12 @@ void MarlinUI::update() {
 
       refresh();
       init_lcd(); // May revive the LCD if static electricity killed it
+      ms = millis();
+      next_lcd_update_ms = ms + LCD_UPDATE_INTERVAL;  // delay LCD update until after SD activity completes
     }
 
   #endif // SDSUPPORT && SD_DETECT_PIN
 
-  const millis_t ms = millis();
   if (ELAPSED(ms, next_lcd_update_ms)
     #if HAS_GRAPHICAL_LCD
       || drawing_screen