Short Pill UI for 3-Button Nav and Taskbar

Added short pill composable and connected repository to interactor to
decide when to show it

Flag: com.android.systemui.enable_underlay
Test: atest NavBarPillScreenshotTest
Test: atest AmbientCueInteractorTest
Test: atest ShortPillScreenshotTest
Bug: 415914274
Bug: 415914083
Change-Id: Ic076d0efc7b262bf979b0daa290e0a83cf860d82