Add hapticChannelsMuted to AudioAttributes

[krocard]

Adds support for hapticChannelsMuted to AudioAttributes, which is required to control audio coupled haptic feedback on supported devices.

The change mirrors the addition of hapticChannelMuted in the platform's android.media.AudioAttributes in API 29.

In particular, this changes allows to use the HapticGenerator audio effect with ExoPlayer.

Test

Snippet addapted from HapticGenerator documentation):

val audioSessionId = audioManager.generateAudioSessionId()
val player = Player.Builder().setAudioSessionId(audioSessionId).build()
if (HapticGenerator.isAvailable()) {
     HapticGenerator.create(audioSessionId).setEnabled(true)
 }

Play and check that the phone vibrates in sync with the audio.

[google-cla]

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[icbaker]

Thanks Kevin! This looks like it goes a bit of the way towards #2677.

[microkatz]

@krocard

Thanks Kevin! Would you mind signing the cla/google before we can take a look at reviewing your PR?

[krocard]

It's in progress. It should be sorted out today.
Edit: We are still working on it.
Edit2: We might have to submit a new one as our old CLA doesn’t seem to be working