UID mixing rule support both RECORDERS and PLAYERS mix type

Export API in AudioMixingRule#Builder to allow application specify the mix type when using UID mixing rule.

Bug: 169964607
Test: atest com.google.android.gts.audio.AudioHostTest, manual testing
Change-Id: Icf7c83f280aeec7b11aa3bc43fb31657c863e7fd
2 files changed