audio/media: Destroy transport if SetConfiguration fails

audio/media: Destroy transport if SetConfiguration fails

set_configuration creates a transport before calling SetConfiguration on
the MediaEndpoint1 DBus interface.  If this DBus call fails the
transport sticks around while it should instead be cleaned up.

When the peer retries or reconnects (in case of BlueZ which cuts the
connection due to a missing recount [1]) set_configuration finds this
old transport and returns FALSE.  The peer will never succeed this call
unless it randomly decides to call clear_configuration or BlueZ is
restarted.

[1]: https://marc.info/?l=linux-bluetooth&m=160364326629847&w=2

Signed-off-by: Anuj Jain <anuj01.jain@samsung.com>
Signed-off-by: Ayush Garg <ayush.garg@samsung.com>