Bluetooth: BAP: Broadcast Source: Update stream codec config data

When creating a BAP broadcast source with bt_bap_broadcast_source_create
only the subgroup information is stored in the streams and the remaining
BIS specific information is not stored in the stream->codec_cfg,
which it should.
Fix is to store bis specific information also in stream codec config.
Updated broadcast source BSIM test to verify above usecase.

Signed-off-by: Nithin Ramesh Myliattil <niym@demant.com>