Sharesheet - Fix regression in direct share sorting

When mutiple apps share shortcuts and are given to the UI to display,
the ranked order from both the App Prediction Service and the legacy
ranker is inadvertently being discarded. This means that targets the
user almost never uses will now be shown as high priority, causing
confusion and pretty horrible user experience.

Address the issue by adding in a score for shortcuts, based on the
index in the ordered list.

Bug: 136201796
Test: atest ChooserActivityTest and manually compare results from
      AppPredictionService to verify order is consistent
Change-Id: I1fe2c2d2e13195f6f6c3a5818fade4844c15488e