Remove unnecessary default
Remove unnecessary default

The fallthrough default was not needed as all environments already have
the required configuration.

ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-public,ministryofjustice/prison-visits-2,ministryofjustice/prison-visits-2