gdk_window_move_to_rect() does not reposition already shown window

When a GdkWindow is already positioned by gdk_window_move_to_rect() and shown, all subsequent gdk_window_move_to_rect() calls to this window does not have any effect. It's because xdg_positioner is created/updated only from gdk_wayland_window_create_xdg_popup() which is called in map() only.

A workaround is to encapsule gdk_window_move_to_rect() by gtk_window_hide()/gtk_window_show().