KRACOEUS-7999: Stack trace when trying to view undisclosed Events

More instances where I converted lookups to DataObjectService, for fetching DevelopmentProposal and ProposalPerson objects.
@tharpgc I'll let @gathreya make a decision on when to fix this, but its an obvious problem and we shouldn't ignore it when we are already fixing the code, despite the fact that its a refactoring, a minor one at that.