Add ComplicationType in ComplicationProvider.

The ComplicationProvider interface now requires any implementation to
define the type(s) of the complicaiton it provides. It also converts the
type from DreamBackend to avoid dependency.

Test: atest com.android.systemui.dreams.ComplicationProviderTest
Fix: 214038720
Change-Id: Id4a41d961dbd0f3838a3a29b7524d30d7bd10b31