[SysUI][Floaty] Move to Animatable to ensure window destruction

Due to custom delays in squeeze animation, animateFloatAsState's
finishedListener is not super handy to invoke effect window's
destruction. This CL moves the animation logic to use Animatable
to handle custom delays as well as destruction of effects window.

Bug: 399263897
Flag: com.android.systemui.shared.enable_lpp_assist_invocation_effect
Change-Id: I65a60d4734fc5ed952957a71150ab49493728035