media: clear the right transport when clearing BAP endpoint

media: clear the right transport when clearing BAP endpoint

Each configured BAP stream is associated with a transport, and only that
transport should be cleared when the stream's configuration is cleared.

This is required for multiple BAP clients to use the same Media1
endpoint, which is what we should aim for to follow the spirit in which
the endpoints work in ASCS.  Sound servers generally can handle this,
since the *Configuration calls provide the transport paths, and for
different clients they are associated with different devices.