Make `bt_hci_cmd_send_sync` return `-EACCES` when receiving
`BT_HCI_ERR_CMD_DISALLOWED`.
Update some tests that were expecting `-EIO` when
getting `BT_HCI_ERR_CMD_DISALLOWED`.
Add a warning in `set_random_address` when getting that new error. This
is done in case someone try to set a new random address while legacy
advertising, scanning or initiating is enabled. This is illegal behavior
according to the Core Spec (see Vol 4, Part E 7.8.4).
Signed-off-by: Théo Battrel <theo.battrel@nordicsemi.no>
76559f27fd