[v2.0] Relay after argument not working for custom functions

[PedroBern]

Related #5658

Relay after argument not working in v2.0.

Repro

Take a custom function and run:

query MyQuery {
  my_custom_function_connection(args: {seed: "0.5"}, first: 2) {
    edges {
      node {
        id
        pk
      }
      cursor
    }
  }
}

The response will be something like this:

{
  "data": {
    "my_custom_function_connection": {
      "edges": [
        {
          "node": {
            "id": "WzEsICJwdWJsaWMiLCAid29kIiwgNDJd",
            "pk": 42
          },
          "cursor": "eyJwayIgOiA0Mn0="
        },
        {
          "node": {
            "id": "WzEsICJwdWJsaWMiLCAid29kIiwgMzFd",
            "pk": 31
          },
          "cursor": "eyJwayIgOiAzMX0="
        }
      ]
    }
  }
}

Now, do one more query, with the after argument being the cursor of the first node:

query MyQuery {
  my_custom_function_connection(args: {seed: "0.5"}, first: 2, after: "eyJwayIgOiA0Mn0=") {
    edges {
      node {
        id
        pk
      }
      cursor
    }
  }
}

received:

{
  "data": {
    "my_custom_function_connection": {
      "edges": [
        {
          "node": {
            "id": "WzEsICJwdWJsaWMiLCAid29kIiwgNTNd", expected "WzEsICJwdWJsaWMiLCAid29kIiwgMzFd"
            "pk": 53 expected 31
          },
          "cursor": "eyJwayIgOiA1M30="
        },
        {
          "node": {
            "id": "WzEsICJwdWJsaWMiLCAid29kIiwgNDVd",
            "pk": 45
          },
          "cursor": "eyJwayIgOiA0NX0="
        }
      ]
    }
  }
}

Expected the first node in the second query to be the same as the second node in the first query. But it wasn't.