Default to RankerResolver if AppPredictor is disabled

The AppPredictionServiceResolverComparator will use the ResolverRankerService
if APS appears to be disabled for share activities (returning empty despite
being given a non-empty target list).

For Direct share targets, if the share target list returned is empty, we fall
back on calling the ShortcutManager directly and relying on ChooserTargetService
to rank.

Bug:129014961
Test:Manually tested.
Test: atest frameworks/base/core/tests/coretests/src/com/android/internal/app
Change-Id: I9891a3a4d879e247b84a651408058153ea57c766