Merge "Grab audio focus when starting Voice actoins. tested in pi (go/ag/3974655)."

am: b835703500

Bug: 76031221

Test: tested manually. Start Local media player. From
KitchenSink->HeadSet Audio->"Start Voice Interaction".
Ask a question. Local media should stop, Should hear the anwer.
and then Local media should resume playing.

Change-Id: I97136a0eb00468c10d74037c790b75e3eb4b7835
(cherry picked from commit c28c7a20bab6cab1954c15393948fb7ed79b3366)