[BUG] xtrabackup error: Job.batch is invalid: spec.template.spec.containers[0].env[4].valueFrom.secretKeyRef.key: Required value

[JashBook]

Describe the bug
xtrabackup error:
Creating backup failed, error: Job.batch "dp-backup-backup-default-mysql-opuiou-20231011101333-efe30e16" is invalid: [spec.template.spec.containers[0].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[0].env[5].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[5].valueFrom.secretKeyRef.key: Required value]

kbcli version
Kubernetes: v1.26.3
KubeBlocks: 0.7.0-beta.0
kbcli: 0.7.0-beta.0

To Reproduce
Steps to reproduce the behavior:

1. create cluster
2. do xtrabackup
3. See error

kubectl get backup
NAME                                         POLICY                             METHOD       REPO                    STATUS   TOTAL-SIZE   DURATION   CREATION-TIME          COMPLETION-TIME   EXPIRATION-TIME
backup-default-mysql-opuiou-20231011101333   mysql-opuiou-mysql-backup-policy   xtrabackup   backuprepo-kbcli-test   Failed                           2023-10-11T02:13:33Z                     2023-10-18T02:13:33Z

describe backup

kubectl describe backup backup-default-mysql-opuiou-20231011101333
Name:         backup-default-mysql-opuiou-20231011101333
Namespace:    default
Labels:       app.kubernetes.io/instance=mysql-opuiou
              app.kubernetes.io/managed-by=kubeblocks
              apps.kubeblocks.io/component-name=mysql
              dataprotection.kubeblocks.io/backup-repo-name=backuprepo-kbcli-test
              dataprotection.kubeblocks.io/backup-type=Full
              dataprotection.kubeblocks.io/cluster-uid=bc6a8b30-42fc-4d94-8916-fdd0e4f2ca32
              kubeblocks.io/backup-protection=retain
Annotations:  dataprotection.kubeblocks.io/target-pod-name: mysql-opuiou-mysql-0
              kubeblocks.io/cluster-snapshot:
                {"metadata":{"name":"mysql-opuiou","namespace":"default","creationTimestamp":null},"spec":{"clusterDefinitionRef":"apecloud-mysql","cluste...
API Version:  dataprotection.kubeblocks.io/v1alpha1
Kind:         Backup
Metadata:
  Creation Timestamp:  2023-10-11T02:13:33Z
  Finalizers:
    dataprotection.kubeblocks.io/finalizer
  Generation:        1
  Resource Version:  729635
  UID:               efe30e16-8085-46f6-b318-cdf014622a55
Spec:
  Backup Method:       xtrabackup
  Backup Policy Name:  mysql-opuiou-mysql-backup-policy
  Deletion Policy:     Delete
  Retention Period:    7d
Status:
  Actions:
    Action Type:  Job
    Name:         dp-backup
    Phase:        New
  Backup Method:
    Action Set Name:   xtrabackup-for-apecloud-mysql
    Name:              xtrabackup
    Snapshot Volumes:  false
    Target Volumes:
      Volume Mounts:
        Mount Path:              /data/mysql
        Name:                    data
  Backup Repo Name:              backuprepo-kbcli-test
  Expiration:                    2023-10-18T02:13:33Z
  Failure Reason:                Job.batch "dp-backup-backup-default-mysql-opuiou-20231011101333-efe30e16" is invalid: [spec.template.spec.containers[0].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[0].env[5].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[5].valueFrom.secretKeyRef.key: Required value]
  Format Version:                0.1.0
  Path:                          /default/mysql-opuiou-bc6a8b30-42fc-4d94-8916-fdd0e4f2ca32/mysql/backup-default-mysql-opuiou-20231011101333
  Persistent Volume Claim Name:  pvc-backuprepo-kbcli-test-sfn6wv
  Phase:                         Failed
  Start Timestamp:               2023-10-11T02:13:33Z
  Target:
    Connection Credential:
      Host Key:      host
      Password Key:  
      Port Key:      port
      Secret Name:   mysql-opuiou-conn-credential
      Username Key:  
    Pod Selector:
      Match Labels:
        app.kubernetes.io/instance:         mysql-opuiou
        app.kubernetes.io/managed-by:       kubeblocks
        apps.kubeblocks.io/component-name:  mysql
        kubeblocks.io/role:                 follower
      Strategy:                             Any
    Service Account Name:                   kb-mysql-opuiou
Events:
  Type     Reason               Age    From               Message
  ----     ------               ----   ----               -------
  Normal   CreatingJob          8m14s  backup-controller  creating job default/dp-backup-backup-default-mysql-opuiou-20231011101333-efe30e16
  Warning  FailedCreatedBackup  8m14s  backup-controller  Creating backup failed, error: Job.batch "dp-backup-backup-default-mysql-opuiou-20231011101333-efe30e16" is invalid: [spec.template.spec.containers[0].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[0].env[5].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[4].valueFrom.secretKeyRef.key: Required value, spec.template.spec.containers[1].env[5].valueFrom.secretKeyRef.key: Required value]

Expected behavior
xtrabackup successs.

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[JashBook]

fix via #5342