Fix TextClassifier.getTextClassificationResult()

Gracefully handles situations where a default app cannot be found
to handle the intent.

1. If we can not find any app to handle the intent,
   do not include an "assist" menu item entry to fire the intent.
   Also, do not linkify the entry.
2. If we do not have a default app to handle the intent,
   show a generic title for apps that will handle the intent
   and do not include an icon.

In the ideal case where we find a default app to include the intent,
show the app's (preferably activity's) title and icon.

Test: Manually tested. There's an AI to write more automated tests.
Bug: 34777322
Bug: 34927631
Change-Id: Ia94efbbdda3da8f181fac9228cd2d3a76cb727d3