Headset: App exception aren't from SystemServer

Calling into IBluetoothHeadset will call the HeadsetService from
Bluetooth app that does not live in the systemServer.
Therefore, exception should be rethrown as runtimeException

Bug: 298264617
Test: atest CtsBluetoothTestCases | Cts does not handled failure in the
      binder nor any of the Test framework we currently have
Change-Id: I617c28686fc3af639b2ca980129974633403ff2f