Invoke redraw callback for wallpaper if size is changed

As the comment of SurfaceHolder.Callback2#surfaceRedrawNeeded:
Called when the application needs to redraw the content of its
surface, after it is resized or for some other reason.

In case some path other than handleResized calls updateSurface
without requesting redraw but triggers a size change.

Bug: 283952978
Test: Unlock to an app with different orientation and off/on
      screen again quickly.
Change-Id: I9951bc85628e93547d36a2936e3c7c6162d55c49