Exclude BusinessSupportEditions with non-live artefacts in results.

It's possible to archive an artefact associlated with a BusinessSupportEdition
making the content go away but still searchable via the API. 
So filter results to exclude non-live artefacts.
https://govuk.zendesk.com/agent/#/tickets/821973

The styleguide says things like this should be avoided: `Never chain do...end` https://github.com/alphagov/styleguides/blob/master/ruby.md#syntax