Correct patch content for plugin test step in pr-test.yml

This pr is trying to fix wrong patch json while testing plugin in pr-test.yml.

Let's have a look at incorrect patch raw json:

https://github.com/kubesphere/ks-installer/blob/dd5274f536bdcb52fa3738dfb196b9169b7a3d72/.github/workflows/pr-test.yml#L39

and incorrect patch formatted json:

{
  "spec": {
    "alerting": { "enabled": true },
    "auditing": { "enabled": true },
    "enableMultiLogin": { "enabled": true },
    "events": { "enabled": true },
    "logging": { "enabled": true },
    "metrics_server": { "enabled": true },
    "network": { "networkpolicy": { "enabled": true } },
    "store": { "enabled": true }
  }
}

I've already convert the json format into yaml format:

spec:
  alerting:
    enabled: true
  auditing:
    enabled: true
  events:
    enabled: true
  logging:
    enabled: true
  metrics_server:
    enabled: true
  network:
    networkpolicy:
      enabled: true
  openpitrix:
    store:
      enabled: true

Related to #1454

BTW, this PR is no hurry to merge.

/kind bug