Avoid delete whole annotation of users

[LinuxSuRen]

The test output:

root@node1:~# ks get user admin -oyaml | head
apiVersion: iam.kubesphere.io/v1alpha2
kind: User
metadata:
  annotations:
    helm.sh/resource-policy: keep
    iam.kubesphere.io/uninitialized: "true"
    meta.helm.sh/release-name: ks-core
    meta.helm.sh/release-namespace: kubesphere-system
  creationTimestamp: "2021-10-21T04:36:41Z"
  finalizers:
root@node1:~# ks user admin
root@node1:~# ks get user admin -oyaml | head
apiVersion: iam.kubesphere.io/v1alpha2
kind: User
metadata:
  annotations:
    helm.sh/resource-policy: keep
    iam.kubesphere.io/last-password-change-time: "2021-10-21T05:43:00Z"
    iam.kubesphere.io/uninitialized: "false"
    meta.helm.sh/release-name: ks-core
    meta.helm.sh/release-namespace: kubesphere-system
  creationTimestamp: "2021-10-21T04:36:41Z"

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Codecov Report

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@@            Coverage Diff            @@
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[JohnNiang]

In my test, even if we changed the annotation iam.kubesphere.io/uninitialized to false, I didn't see the annotation value back to true.