Returning error from subscription doesn't return a proper Graphql Error payload

[MohamedSabthar]

Description:
Consider the following graphql service and the subscription query
Service

service /graphql on new graphql:Listener(4000) {

    resource function get geeting() returns string {
        return "Welcome to Book Review Service";
    }

    resource function subscribe data() returns stream<int, error?>|error {
        return error("an error occured");
    }
}

Query

subscription {
  data
}

The above query returns the following output

{
  "type": "error",
  "id": "1",
  "payload": [
    {
      "message": "an error occurred"
    }
  ]
}

which does not conform to the standard format for GraphQL errors. The expected error response should include additional information such as the location and path of the error. Following is the expected response

{
  "type": "error",
  "id": "1",
  "payload": [
    {
      "message": "an error occurred",
      "locations": [
        {
          "line": 2,
          "column": 3
        }
      ],
      "path": [
        "data"
      ]
    }
  ]
}

Steps to reproduce:

Affected Versions:
Update 3,4

OS, DB, other environment details and versions:

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