Rescue from GdsApi::HTTPNotFound errors when unpublishing a section
Rescue from GdsApi::HTTPNotFound errors when unpublishing a section

A manual section may have already been unpublished in the relevant
publishing app.  If we try to unpublish it again here when updating
a manual, a 404 error is returned from publishing-api.

This allows the update of the manual to continue when the section
has already been removed elsewhere.

alphagov/manuals-publisher,alphagov/manuals-publisher,alphagov/manuals-publisher