Regression: accepting request for deleting no longer works when a document has been published once

The FullRequestWorkflowImpl implementation of acceptRequest hasn't been updated for the new variant state management.
For example for a deleteRequest it only allows it to execute when no published variant exist.
This results in 'no effect' when trying to accept a delete request through the CMS (no feedback, neither in the console).

Other conditions and checks in FullRequestWorkflowImpl likewise are now incorrect.