[BUG] Removing Backend credentials not working

首先跟踪 publisher.Program 中的后端 PUT 请求，以及发送到 Azure API Management backends 终结点的凭据 payload。复现从证书更新为空凭据的操作，并验证发布成功，且不会保留旧证书或返回验证错误。

Release version

APIOps latest

Describe the bug

We want to remove the credentials from a backend configuration while puclishing.
So when overwritting the configuration, we set the array to empty for both certificate and certificateIds.

The configuration is set as follows:

backends:
  - name: "my-backend"
    properties:
      url: "https://example.com"
      credentials:
        certificate: []
        certificateIds: []

However, we still get the error of missing certificate when we try to publish this without the certificate.

Expected behavior

Backend created without any credentials and errors

Actual behavior

We are getting validation error.

crit: Publisher[0]
      System.Net.Http.HttpRequestException: HTTP request to URI https://management.azure.com/subscriptions/***/resourceGroups/***/providers/Microsoft.ApiManagement/service/***/backends/my-backend?api-version=2022-04-01-preview failed with status code 400. Content is '{"error":{"code":"ValidationError","message":"One or more fields contain incorrect values:","details":[{"code":"ValidationError","target":"credentials","message":"Certificate with id 'my-cert' not found."}]}}'.
         at common.HttpPipelineExtensions.Validate(Response response, Uri requestUri)
         at common.HttpPipelineExtensions.PutResource(HttpPipeline pipeline, Uri uri, JsonObject resource, CancellationToken cancellationToken)
         at publisher.Program.<>c__DisplayClass12_0.<<GetPutRestResource>b__0>d.MoveNext()

Reproduction Steps

Create a backend with certificate credentials.

and try to publish a new one without certificate credentials.