Bluetooth: controller: Fix CIS Central FT calculation

For config CONFIG_BT_CTLR_CONN_ISO_RELIABILITY_POLICY, set
CIG_Sync_Delay fixed as high as possible, and calculate FT by iteration.
This favors utilizing as much as possible of the Max_Transport_latency,
and spreads out payloads over multiple CIS events (if necessary).

Add exit with cleanup as ll_cig_parameters_commit may fail after
creating new CIG/CIS instances.

Fixes issue #59605.
Fixes EBQ test HCI/CIS/BI-12-C.

Signed-off-by: Morten Priess <mtpr@oticon.com>