15/ Move some more logic into gesture/device state

- Bake overview/home component into the gesture state (it should never
  change mid-gesture), this allows us to remove OverviewComponentObserver
  refs from the handlers
- Move nav bar position into DeviceState
- Remove passing RecentsModel into the handlers, it already partially
  references it statically

Bug: 141886704
Change-Id: I62f9138651cbe1fb984b57b96e4212ebaa1ffb5d