Nested resource in sib-form has no @id

When a sib-form contains a nested resource, it does not send the corresponding @id to the server when submitted.

For example:

<sib-form
  data-src="https://api.test-paris.happy-dev.fr/projects/3/"
  fields='customer.name, name'
></sib-form>

We get this data:

{
  "customer": {
    "name": "Privjet kustomer"
  },
  "name":"Privjet"
}

We expect this:

{
  "customer": {
    "@id": "https://api.test-paris.happy-dev.fr/customers/3/",
    "name": "Privjet kustomer"
  },
  "name":"Privjet"
}