Pass transition token to finish() for Keyguard

Since we don't control the threads used for the animations, we can get
the finish callbacks in the wrong order or multiple times which can lead
to calling the same finish method multiple times (harmless but spammy)
or a later finish method at the wrong time. Avoid this by keeping a map
of callbacks that are still eligible for sending to the transition
controller.

Bug: 286242775
Bug: 286507622
Test: atest WMShellUnitTests:ShellTransitionTests
Test: atest KeyguardTests
Test: atest DreamManagerServiceTests
Change-Id: Iab2abf74d73e6dad24e1d12b08162a7514653e32