CameraService: Treat TOP_SLEEPING same as TOP for priority.

When arbitrating between camera clients, treat processes in the
TOP_SLEEPING state with the same high priority as processes in the
TOP state.

This resolves race conditions during lock screen handoffs between
clients such as face unlock (a bound foreground process) and a
secure camera app (the topmost activity, but transitioning from
TOP_SLEEPING to TOP asynchronously from the activity lifecycle
callbacks).

Bug: 23731720
Change-Id: I92c3f8f561c7725627826c0ba3dc926e99af746c