Reinstate deployments updating scheduled pipeline

The job currently always fails. This was useful for seeing in GitLab UI merge requests whether they were deployed to GitLab the product.

See https://gitlab.com/gitlab-org/gitlab-services/design.gitlab.com/-/blob/c90062c29aa9137e5ef06bd6395836b1ae990fac/packages/gitlab-ui/.gitlab-ci.yml#L372-389.