CameraService: Create a dummy stream when 0 streams are requested.

A workaround for a camera device HAL v3.2 or older specification hole - it's
not acceptable to configure_streams with 0 output streams. However, we allow for
this at the public API level, to allow an application to release all output streams.

So in this case, create a dummy stream that doesn't actually do anything as a placeholder.

Bug: 17220694
Change-Id: Ib25242ffc2c9f2b2f619fd5fe6d652266579da85