When using JSON as output format, we want objectReference values to be
represented as a struct. For example, "item" is such a value:
{"ts":1678135015708.349,"caller":"garbagecollector/garbagecollector.go:595","msg":"classify object references","v":5,"item":{"name":"dra-test-driver-g4tkd","namespace":"dra-1830","apiVersion":"v1","uid":"c3f88616-7282-488c-887c-3f04291e6f4f"},"solid":null,"dangling":[{"apiVersion":"apps/v1","kind":"ReplicaSet","name":"dra-test-driver","uid":"dbe9a90c-9dfd-4ad0-8395-e5fa228f9851","controller":true,"blockOwnerDeletion":true}],"waitingForDependentsDeletion":null}