Re-init HotwordDetectionSrvc when audioserver dies

We do this instead of simply sending over the new binder to avoid race
conditions with audio reading in the service.

Fix: 190011174
Test: manual - kill audio server, also do this twice in quick
 succession; dsp and non-dsp
Test: atest CtsVoiceInteractionTestCases
Change-Id: Iabee9549512cc09d2305de5b0e965b9315134fb0