OnRep_Controller is not called when Controller is set in AController::OnRep_Pawn()

We don't call OnRep_Controller after it's set to null in AController::OnRep_Pawn, so overridden implementations won't get called.

While it's a little weird to call OnReps explicitly on the client outside of the actual replication system, there is some precedent in other parts of the pawn/controller/possession logic, like in APlayerController::ClientRetryClientRestart_Implementation and AController::SetPawnFromRep.

Need to evaluate whether this suggestion is the right path forward.