Embargo: Workflow events should only trigger the embargo workflow if the user is in an embargo group

Right now the workflow events are called when a document is:
a) added
b) copied

These WorkflowEventWorkflow classes now always call the embargo workflow even though the user is not in an embargo group.
It might make sense to do an additional check before calling the actual embargo workflow to see if the user is in an embargo group.
The embargo workflow itself also does this check, so I might give a little overhead.