Notify home is visible when launching a translucent app.

To fix the taskbar stash delay when launching an app, ag/18875100
sets the state so that the taskbar stashes immediately after
app is launched.

Since we cannot know if the app is translucent at that point,
we have to check after the animation is started so we can update the
launcher visibility state.

Bug: 314792981
Flag: ACONFIG ENABLE_HOME_TRANSITION_LISTENER TRUNKFOOD
Test: HomeObserverTest
Change-Id: Ifc3a6559d7a8c6fda4c08a0fc2d6791da46b38d6