Only add entry with unique package name to default browser list.

When we query the package manager for activities that can handle the
web data uri, different capable activities within the same package will
be returned as separate entries. However, when we show the default
browser apps to the user, the entries are simply base on package name.
So, if there are multiple activities within the same package that can
handle the web data, they will be shown as duplicate entries.

When we process the resolved activities, check the corresponding package
name for duplicate entries before adding it to the default browser list.

Change-Id: I70c88866eb3d5fe6466554749e23c85f429dd30c
Fixes: 84207432
Test: make RunSettingsRoboTests