Enable publish_topics in production
Enable publish_topics in production

HMRC are ready to publish their manuals into GOV.UK production. This commit enables `publish_topics` for HMRC Manuals API to publish topics to Rummager in Production
alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet