Sharesheet - Fix crash when suspended app is selected

After selecting a suspended app, the package monitor would be
unregistered even though the app would never be launched. This would
cause an IllegalStateException on the next selection of any target,
and crash the sharesheet. Check for a suspended target before
unregistering.

Fixes: 160015744
Test: manual, follow BR steps and pause an app
Change-Id: I1b0c79bad0fa75aea6a543b6f8a4848720faa0c8