Remove ChooserTargetServiceConnection from adapter

In the new flow, ChooserListAdapter didn't actually depend
on this data for anything (and ChooserActivity only ever
sent an empty list). In preparation for removing the
(internal) ChooserTargetServiceConnection class altogether,
this CL removes it from the ChooserListAdapter API: the
only reference outside of ChooserActivity.

Test: compiles.
Change-Id: I2c379562e47fba405714b08632118af2e16d8a40