Allow INTERACT_ACROSS_USERS for service access.

But only if the two users are in the same profile.  Also
apply the same rule for the recently allowed interaction
across content providers.

The activity manager now keeps track of which users are in
the same profile group, and the handleIncomingUser function has
an option to allow a non-full caller to do the interaction
if the two users are in the same profile group.

Spread this joy all over the place.

Also turn off multi-user on Svelte devices.

Change-Id: I231484ea2a6bfccbb3cd51357d7a387bd75039ea