Require homing to toggle leveling (#13652)

Marlin/src/lcd/menu/menu_motion.cpp

@@ -465,7 +465,7 @@ void menu_motion() {
     #if DISABLED(PROBE_MANUALLY)
       MENU_ITEM(gcode, MSG_LEVEL_BED, PSTR("G28\nG29"));
     #endif
-    if (leveling_is_valid()) {
+    if (all_axes_homed() && leveling_is_valid()) {
       bool new_level_state = planner.leveling_active;
       MENU_ITEM_EDIT_CALLBACK(bool, MSG_BED_LEVELING, &new_level_state, _lcd_toggle_bed_leveling);
     }