Add isAudioOn() in HeadsetProfile

* Add this API for checking audio status from BlueTooth Headset Service

Bug: 74130772
Test: ROBOTEST_FILTER="HeadsetProfileTest" make -j40 RunSettingsLibRoboTests
Change-Id: I80b3dbc8b0f9926859ff08f6849cafca89e940a7
2 files changed