How to call custom function with the id provided by the relay preset
### Summary

I'm trying to set up a function like this:

```sql
CREATE
OR REPLACE function dansdata.add_organization_member (
  organization_id UUID,
  individual_id UUID,
  title TEXT
) returns dansdata.organization_members AS $$
  INSERT INTO dansdata.organization_members("organization_id", "individual_id", "title") VALUES (organization_id, individual_id, title) RETURNING *;
$$ language sql volatile strict security invoker;
```

However, attempting to call the function like this (using the relay preset) does not seem to work:

```gql
mutation {
  addOrganizationMember(input: {
    organizationId: "WyJPcmdhbml6YXRpb24iLCI3YjA4OGVkOC0wYzkzLTRlZTUtODdlYi05YWU4NTMxZDgwMGYiXQ",
    individualId: "WyJJbmRpdmlkdWFsIiwiNjU3YmI0ODMtOGUzNy00ODA2LTlkYzAtMWZjZGM0OWEzMTkxIl0",
    title: "Developer"
  }) {
    result {
      id
      title
      individual {
        name
      }
      organization {
        name
      }
    }
  }
}
```

<details><summary>Error</summary>

```json
{
  "errors": [
    {
      "message": "Invalid UUID, expected 32 hexadecimal characters, optionally with hypens",
      "extensions": {}
    },
    {
      "message": "Invalid UUID, expected 32 hexadecimal characters, optionally with hypens",
      "extensions": {}
    }
  ]
}
```

</details>

Instead, it seems I need to use the actual `rowId` instead:

```gql
mutation {
  addOrganizationMember(input: {
    organizationId: "7b088ed8-0c93-4ee5-87eb-9ae8531d800f",
    individualId: "657bb483-8e37-4806-9dc0-1fcdc49a3191",
    title: "Developer"
  }) {
    result {
      id
      title
      individual {
        name
      }
      organization {
        name
      }
    }
  }
}
```

which is very inconvenient given that `rowId` isn't available when using the relay preset.

The [documentation](https://postgraphile.org/postgraphile/next/node-id#more-on-the-relay-preset:~:text=(and%2C%20with%20a%20little%20guidance%2C%20in%20function%20inputs).) mentions that the relay preset "[...] will hide raw primary keys from most of the schema, and will use global object identifiers instead - not just in the query schema but also in mutations and filtering (and, **with a little guidance, in function inputs**).".

Given this, I'm assuming my first example is supposed to work but that I need to add some sort of configuration somewhere. Unforutnately, the current documentation does not currently elaborate on what "a little guidance" entails.

### Additional context

PostgreSQL: docker - `postgis/postgis:16-3.4-alpine`
Node: v20.14.0
Postgraphile: 5.0.0-beta.26
