"Empty Payload. JSON content expected." when posting a comment with SDK v6

Describe the bug

"Empty Payload. JSON content expected." error is thrown when trying to add a comment on an Alert v2.

com.microsoft.graph.models.odataerrors.ODataError: Empty Payload. JSON content expected.
	at com.microsoft.graph.models.odataerrors.ODataError.createFromDiscriminatorValue(ODataError.java:36)
	at com.microsoft.kiota.serialization.JsonParseNode.getObjectValue(JsonParseNode.java:212)
	at com.microsoft.kiota.http.OkHttpRequestAdapter.lambda$throwIfFailedResponse$0(OkHttpRequestAdapter.java:674)
	at com.microsoft.kiota.ApiExceptionBuilder.<init>(ApiExceptionBuilder.java:26)
	at com.microsoft.kiota.http.OkHttpRequestAdapter.throwIfFailedResponse(OkHttpRequestAdapter.java:673)
	at com.microsoft.kiota.http.OkHttpRequestAdapter.sendCollection(OkHttpRequestAdapter.java:200)
	at com.microsoft.graph.security.alerts_v2.item.comments.CommentsRequestBuilder.post(CommentsRequestBuilder.java:72)
	at com.microsoft.graph.security.alerts_v2.item.comments.CommentsRequestBuilder.post(CommentsRequestBuilder.java:56)

HTTP response status code is 400 "bad request".

Expected behavior

A comment is created on the alert, without any error.

For instance, posting the same request with Curl works perfectly:

curl -X POST \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{
    "@odata.type": "microsoft.graph.security.alertComment",
    "comment": "Your comment here"
  }' \
  "https://graph.microsoft.com/v1.0/security/alerts_v2/{alertId}/comments"

How to reproduce

I followed the instructions from the documentation (https://learn.microsoft.com/en-us/graph/api/security-alert-post-comments?view=graph-rest-1.0&tabs=java):

GraphServiceClient graphClient = new GraphServiceClient(requestAdapter);

com.microsoft.graph.models.security.AlertComment alertComment = new com.microsoft.graph.models.security.AlertComment();
alertComment.setOdataType("microsoft.graph.security.alertComment");
alertComment.setComment("Demo for docs");
var result = graphClient.security().alertsV2().byAlertId("{alert-id}").comments().post(alertComment);

but converted that code into Kotlin.
The post() method, contrary to the documentation need a list of comments as input instead of a single comment.

val comment = AlertComment()
comment.odataType = "microsoft.graph.security.alertComment"
comment.comment = "my comment"
graphClient.security().alertsV2().byAlertId(alertId).comments().post(listOf(comment))

Debugging the request, I can see that the payload send by the SDK is [{"comment":"my comment","@odata.type":"microsoft.graph.security.alertComment"}] instead of {"comment":"my comment","@odata.type":"microsoft.graph.security.alertComment"} as it should be.

SDK Version

6.13.0

Latest version known to work for scenario above?

unknown

Known Workarounds

No response

Debug output

</details>


### Configuration

_No response_

### Other information

_No response_

Start at security/alerts_v2 item comments CommentsRequestBuilder.post, using the stack trace and the AlertComment reproduction to trace request serialization. Compare the SDK body with the curl payload; done means posting one AlertComment sends a JSON object rather than a one-element array and creates the comment successfully.