window: Always save the user_rect when resizing Wayland windows

The user_rect represents the unconstrainted window size, and lots
of code in mutter assumes it can resize to the user_rect at any
time. If we wait for an attach to ACK and save the user rect, we'll
see lots of flickering as code is resizing to the old user_rect
at any time.

src/core/window.c

@@ -5082,6 +5082,7 @@ meta_window_move_resize_wayland (MetaWindow *window,
 
   meta_window_move_resize_internal (window, flags, NorthWestGravity,
                                     x, y, width, height);
+  save_user_window_placement (window);
 }
 
 /**