fix(override): support overwriting finalizers via OverridePolicy

[JackZxj]

Now you can use OP to overwrite finalizers like this:

spec:
  overrideRules:
  - overriders:
      jsonpatch:
      - operator: add
        path: /metadata/finalizers/0
        value: aaa.bbb.ccc/test
      - operator: replace
        path: /metadata/finalizers/0
        value: aaa.bbb.ccc/new-test
      # you'd better replace it all instead of removing by index, 
      # because the syncer might remove multiple times by index.
      # - operator: replace 
      #   path: /metadata/finalizers   
      #   value: []
    targetClusters:
      clusters:
      - kubeadmiral-member-2

NOTE: if you have added new finalizers to member cluster's resources, you have to remove all finalizers before you can delete the resource from the member cluster.