Move Stepper::synchronize to Planner (#10713)

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

Marlin/src/lcd/ultralcd.cpp

@@ -570,7 +570,7 @@ uint16_t max_display_update_time = 0;
     no_reentry = true;
     const screenFunc_t old_screen = currentScreen;
     lcd_goto_screen(_lcd_synchronize);
-    stepper.synchronize(); // idle() is called until moves complete
+    planner.synchronize(); // idle() is called until moves complete
     no_reentry = false;
     lcd_goto_screen(old_screen);
   }