Create BluetoothHeadsetSnippet

[Karkeys360]

Updated bluetooth profile snippets to include BluetoothHeadsetSnippet.

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[xpconanfan]

This class does not follow the convention of MBS, so I'm not sure if it belongs here.
You are just using bt adapter APIs to perform a specific scenario.
MBS is meant to be a think layer that exposes Android APIs.

You can freely use any snippet class you have in conjunction with MBS without adding it to MBS.

[xpconanfan]

Could you fix the google cla requirement?