Bluetooth: Enable in-band ringing in vibration mode (1/4)

* Add AudioSystem.FOR_VIBRATE_RINGING mode to match the native layer
  AUDIO_POLICY_FORCE_FOR_VIBRATE_RINGING force mode
* Switch to this mode when Bluetooth SCO is connected
* Modify AudioService.muteRingerModeStreams() method to not mute ringer
  volume when Bluetooth SCO is ON. Also, when ringer is unmuted, mirror
  speaker ringtone volume on Bluetooth SCO ringer

Bug: 72647074
Test: Call phone in vibration mode and hear ringtone on HFP enabled
      headset, verify that ringtone is only played through headset.
      Then disconnect headset and call again to verify that ringtone
      does not play through phone speaker in vibration mode.

Change-Id: I7d642020710c085f0e1f27c750c74b0e2fb57398