Mute haptic channels by default.

In case the apps start vibration while playing asserts containing haptic
channels, it will be safer to mute haptic channels by default. Apps will
need to explicitly enable haptic channels if they want haptic via audio.

Bug: 129544270
Test: play with/without enabling haptic channels.
Change-Id: Id35d25c2be1c0b26053389f0b277b1ce321ad29e