LeBroadcastAssistant: App exception aren't from SystemServer

Calling into IBluetoothLeBroadcastAssistant  will call the
BassClientService 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: Idbe116bfc6b41b11e2d6f9fd4b092f764e9df4ac