PbapClient: App exception aren't from SystemServer

Calling into IBluetoothPbapClient will call the PbapClientService 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: I2fe53581f12ce7f40d96ed9450b10f52fd89211a