[22/n] Event handling for reachability

Implements ReachabilityGestureListener which receives double
tap events and handle them only if happening outside of the
letterboxed activity bounds.

When the event happens outside of the activity bounds, the
ReachabilityGestureListener triggers a WindowContainerTransaction
to start the reachability animation.

Flag: com.android.window.flags.app_compat_refactoring
Bug: 371500295
Test: atest WMShellUnitTests:ReachabilityGestureListenerFactoryTest
Test: atest WMShellUnitTests:ReachabilityGestureListenerTest
Test: atest WMShellUnitTests:WindowContainerTransactionSupplierTest

Change-Id: Iec2344994e52d719dbdc5793cc7df1c5900d5b58