make sure countries library still returns values
make sure countries library still returns values

to recap the previous commit, in the ward->local authority->county
library we want to return all local authorities and counties. We do this
by excluding anything that doesn't have children.

However, in the countries library, all four countries don't have
children.

I can't think of a generic way to separate these so just filter on the
library id

alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin