Config deletion - Fixed null replacement in json

[hhovsepy]

Issue #6374

At some point " does not exist in json from YAML for deleted array lines.

[josunect]

LGTM.

Verified with a Destination rule: It was not possible to remove name: v2:

kind: DestinationRule
apiVersion: networking.istio.io/v1beta1
metadata:
  name: details
  namespace: bookinfo
  uid: 5353eb43-a9bb-47bd-bbcf-993130106fcd
  resourceVersion: '21906'
  generation: 6
  creationTimestamp: '2023-08-22T12:23:28Z'
  labels:
    kiali_wizard: request_routing
  managedFields:
    - manager: kiali_core
      operation: Update
      apiVersion: networking.istio.io/v1beta1
      time: '2023-08-22T12:42:08Z'
      fieldsType: FieldsV1
      fieldsV1:
        'f:metadata':
          'f:labels':
            .: {}
            'f:kiali_wizard': {}
        'f:spec':
          .: {}
          'f:host': {}
          'f:subsets': {}
spec:
  host: details.bookinfo.svc.cluster.local
  subsets:
    - name: v1
      labels:
        version: v1
    - name: v2
      labels:
        version: v2
status: {}

It is possible to remove now.