Improve fold state provider logic handling posture

Now FOLD_UPDATE_START_CLOSING event is emitted when the angle decreases.
After each angle update, a timeout is started to finish the animation.
When the timeout is reached, FOLD_UPDATE_ABORTED is emitted.

The timeout logic has been moved from
PhysicsBasedUnfoldTransitionProgressProvider to DeviceFoldStateProvider.

This change should not create problems to
FixedTimingTransitionProgressProvider, as it doesn't use any
intermediate FOLD_UPDATE event.

Test: Locally on device
Test atest com.android.systemui.unfold.updates.DeviceFoldStateProviderTest
Bug: 208977663
Change-Id: Ibc5df1e089d6543e7cf6ee2e0ce3d48a0b24cc07