Removal of targets for CapellaIncomingRelation and CapellaOutgoingRelation won't remove the relation

[ewuerger]

Hi,

when deleting the targets of the relations in the title, Capella won't delete these relations. The relations are then kept and the target will be <undefined> (i.e. in the XML file the element won't have the target attribute anymore). Is this behaviour expected or is it a bug? Because the relation doesn't really fit any purpose anymore. I think (I am not 100% sure) on deletion of the target on any other exchangish element (e.g. ComponentExchange) the exchange will be deleted to. So this is inconsistent.

In the end this behaviour necessitates to develop a ModelCleaner such that we reduce workload of our architects.