From dream, FP auth brings you to the last app

Instead of dismissing the activity and bringing
the user to the home screen/launcher.

Test: atest OccludingAppDeviceEntryInteractorTest
Test: use an app and then wait for timeout to dream. When
authenticating with SFPS from the dream, the last app
shows after authentication
Bug: 302196044

Change-Id: I404b2bcaea4e88c9e217c2565af9cd55770dc88c