[Satellite6] Content View delete or promote fails on "Katello::Resources::Candlepin::Environment: 400 Bad Request" error

Issue

• an attempt to delete a Content View / remove a version / disassociate a version from a Lifecycle Environment fails
• another scenario is removal of some repositories from a published Content View and re-publishing it again (what fails)
  • usually, the Content View has many repositories inside
  • the error in foreman task is "Katello::Resources::Candlepin::Environment: 400 Bad Request"