Add Open app in overflow menu

Open app will open the first launcher app found for the package of the
service.

Also:
* refactor how the options are added to the dropdown and use ids instead
  of position. Don't show Add app if there are no other apps to add.
* make menu and dropdown more accessible by requesting focus after
showing.

Test: atest OverflowMenuAdapterTest
Test: manual: open app
Fixes: 265979516
Change-Id: I3c65da89f1013ff5ab75b2f81da2be36e47b66e6