Bluetooth: Controller: Fix window widening for parameter update

When applying the connection parameter update, the window widening
for the previous connection interval was not applied since that is
normally done in LLL

Fixed by applying the window widening in ull_conn_update_parameters()
instead in this case

Fixes EBQ test failure in LL/CON/PER/BV-10-C

Signed-off-by: Troels Nilsson <trnn@demant.com>