A brave new world for window insets (6/n)

Mirror state back to server

In case the client does some local visibility modification to the
leash, the server needs to be informed for a couple of reasons:

- Dispatching state to other apps
- Updating accessibility services
- Updating SystemUI/IME system

For that we send the state back whenever we modified it and send
it via IWindowSession.insetsModified. The server ensures that
visibility state is only updated if we have a match for the
controlling app, and then updates the visibility state and
dispatches it to other apps.

We also invert mHidden to mVisible in InsetsSourceConsumer as it
was really really confusing.

Bug: 118118435
Change-Id: I92f187bf892a5f26b8b007ed7e6fbf4d2c7b13e6