Removes the CIS connection establishment from bt_bap_stream_start
and move the behavior to a new funciton bt_bap_stream_connect.
This has 2 advantages:
1) The behavior of bt_bap_stream_start is much more clear and more aligned
with the spec's behavior for the receiver start ready opcode.
2) It is possible to connect streams in both the enabling
and the QoS configured state with bt_bap_stream_connect as
per the spec. This allows us to pass additional PTS test cases.
To implement this new behavior, samples and tests have been updated.
The CAP Initiator implementation has also been updated
to accomodate for the change in BAP, but the CAP
initiator implementation should work the same for application, except
that it's now possible to do unicast start on ASEs in any order
(https://github.com/zephyrproject-rtos/zephyr/issues/72138).
Signed-off-by: Emil Gydesen <emil.gydesen@nordicsemi.no>