Remove unnecessary validity spec
Remove unnecessary validity spec

This was a leftover from my days of working with teams that would not
lint/check their factories, and would also load their factories with a
lot of test logic that should have been in the specs, proper.

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