[1.1.x] Add optional menu item to toggle software endstops (#10392)

Marlin/ultralcd.cpp

@@ -3109,6 +3109,10 @@ void kill_screen(const char* lcd_msg) {
     START_MENU();
     MENU_BACK(MSG_PREPARE);
 
+    #if HAS_SOFTWARE_ENDSTOPS && ENABLED(SOFT_ENDSTOPS_MENU_ITEM)
+      MENU_ITEM_EDIT(bool, MSG_LCD_SOFT_ENDSTOPS, &soft_endstops_enabled);
+    #endif
+
     if (_MOVE_XYZ_ALLOWED) {
       if (_MOVE_XY_ALLOWED) {
         MENU_ITEM(submenu, MSG_MOVE_X, lcd_move_get_x_amount);