LeBroadcast: App exception aren't from SystemServer

Calling into IBluetoothLeAudio will call the LeAudioService 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: I6adb47ceb1d075f001ff972dded6e44716368363