Let the client know the initial visibility of an InsetsSourceControl

Previously, the client compares the requested visibility with the
source visibility to decide if it needs to play the insets animation or
not. However, the source visibility is not stable while the client is
gaining the control. If the source and the control come from
IWindow#insetsControlChanged, the source has the previous visibility. So
the client can detect the visibility change. If the the source and the
control come from IWindowSession#relayout, the visibility of the source
has been overriden by the requested visibility of the client. So the
client cannot detect the change and cannot play the animation.

This CL lets the client know the initial visibility of the control.
While gaining leash, the client can use the information to decide if
it needs to play animation or not.

Fix: 209064170
Fix: 238496738
Test: atest ImeInsetsSourceConsumerTest InsetsAnimationControlImplTest
      InsetsControllerTest InsetsSourceConsumerTest
      DisplayImeControllerTest
Test: 1. Enable shell transitions
      2. Open camera.
      3. Perform back gesture.
      See if there is status bar animation.
Change-Id: I2c02e97e191ebd83238c0c54908e861d200d4c8d