Don’t return letter contact blocks in service JSON
Don’t return letter contact blocks in service JSON

The admin app doesn’t use them:
https://github.com/alphagov/notifications-admin/search?q=letter_contact_block&unscoped_q=letter_contact_block

Instead it requests them separately when needed:
https://github.com/alphagov/notifications-admin/blob/2f1e8b104b0f8c76e14ba0d0159d0fcaf95a7046/app/models/service.py#L349-L351

Removing this from the response means one fewer database query.

alphagov/notifications-api,alphagov/notifications-api