interact should update editors only once for each event
This is a follow-up of !554. The
interact task currently updates the editor and writes to the SDS again until the editor does not write new values any more. This means that editors are updated at least twice per event which wastes performance and can also lead to infinite loops in case the interaction between editors and SDSs does not reach a fixedpoint.
The editors should only be updated once, BUT the editor value should still reflect the values produced by the editor (a test for this was added in !554). For this the SDS has to be read again in case the editors writes a new value.