Go's recents will not have swipe up to overview so there is no need to
have BackgroundAppState. We also do not support quickstep so we don't
need a distinct FastOverviewState. So we stub them out here.
Bug: 114136250
Test: Manual test Launcher3QuickstepGo + NexusLauncher
Change-Id: I9223cd35fc3c64688cda16dcaa1d5f40460c9323