Make IRemoteAnimationFinishedCallback oneway

RA#onAnimationFinished() has been called from the UI thread when
animations finish, causing missed frames (in at least 7 isolated places
in SystemUI.)

On top of that, this method returns void, and it doesn't seem like
there's good reason for halting the main thread until it finishes.

IRemoteAnimationFinishedCallback should follow the same pattern that
IRemoteAnimationRunner does, not blocking the caller.

Bug: 191971782
Test: https://ui.perfetto.dev/#!/?s=556228b5c78df93f1721f62b97a2715d9dd579602bc2c9c0c9812265bdfaec9
Change-Id: Ia257dc4cff64ced20727de9e514fffe3e0ec6186