GitLab Pages external HTTPS setting needs to be set on API
From https://gitlab.com/gitlab-com/support-forum/issues/3314#note_102512587, updating GitLab Pages via the API causes the force HTTPS flag to go false.
This is similar to production#358 (comment 96812921) in that the API nodes need this setting:
gitlab_pages['external_https'] = "0.0.0.0:1443"