Apollo server v4: Status code 200

[laytong]

When we throw validation errors the http code status is set as 400.

When working with apollo router (in a federated graph) this causes the router to throw additional errors

Specifically
https://www.apollographql.com/docs/graphos/routing/errors#SUBREQUEST_HTTP_ERROR

i.e.

"errors": [
    {
      "message": "HTTP fetch failed from 'gql-order': 400: Bad Request",
      "path": [],
      "extensions": {
        "code": "SUBREQUEST_HTTP_ERROR",
        "service": "gql-order",
        "reason": "400: Bad Request",
        "http": {
          "status": 400
        }
      }
    },
    {
      "message": "Variable \"$id\" got invalid value \"uuuuu\". invalid format for id",
      "extensions": {
        "field": "id",
        "context": [
          {
            "arg": "format",
            "value": "id
          }
        ],
        "code": "BAD_USER_INPUT",
        "stacktrace": null
      }
    }
  ]

I think the http status we return should probably be a 200 not a 400 because
a. The request isn't actually malformed, we are just throwing an error due to business logic.
b. we don't want to trigger SUBREQUEST_HTTP_ERROR

If you don't fully agree, perhaps we could add an option to the apollo server v4 plugin that allows us to configure that status, and not break current behaviour?