Grant HotwordDetectionService RECORD_AUDIO and CAPTURE_AUDIO_HOTWORD.

HotwordDetectionService is an isolated service which ordinarily cannot
hold permissions. An isolated service has its own uid separate from the
owning package.
To allow it to access mic audio, we dynamically override the permissions
check based on the currently bound HotwordDetectionService.

Bug: 190011174
Test: manual - sample app can read audio (with a few other wip changes)
Test: atest CtsVoiceInteractionTestCases
Change-Id: I5abc809546184ef13cb9eb009f916afae6bdf1af