Release the SurfacePackageViewHost on splash screen removed

The SurfacePackageViewHost was never release, leading to a leak of its
surfaces.

This CL ensure it is released:
  - Directly in the shell if the SplashScreenView was not copied
  - From the client, through the window manger and then to the shell if
  the splash screen was copied in the client process

Test: Manually tested with app setting by checking if the surfaces
are actually removed (winscope + logs) in the following scenarios:
    - When the application registers an OnExitAnimationListener
      and calls remove(),
    - When the application registers an OnExitAnimationListener
      and dies without calling remove()
    - When the applicaiton does not register an OnExitAnimationListener
    and the shell removes the splash screen
Bug: 189759180

Change-Id: Ib68bfffad6720911368739d7dd87d8a03034c589