[Rest API or Document Service API] - We cannot update relation with documentId in object but we can with id.
## Bug report

### Required System information

- Node.js version: 20
- NPM version: 9
- Strapi version: 5.7.0
- Database: PostgreSQL
- Operating system: Docker node:20-alpine
- Javascript

### Describe the bug

If we have relation, for exemple Article as one User, we cannot update with `documentId` in object.

That payload works :
```json
{
  "data": {
    "user": 123
  }
}
```

This works : 
```json
{
  "data": {
    "user": {
       "id": 123
    }
  }
}
```

This works:
```json
{
  "data": {
    "user": "ce6j430nb354661pgk1plfjj"
  }
}
```

But this does not work :
```json
{
  "data": {
    "user": {
       documentId: "ce6j430nb354661pgk1plfjj"
     }
  }
}
```
-> 400 error `Invalid key documentId`

And for Repeatable components (it works for Dynamic Zone), it does not work:
```json
{
  "data": {
    "list": [{
      "user": {
         "id": 123
        }
    }]
  }
}
```

### Steps to reproduce the behavior

1. On collection with REST API
2. Try to create or update a new entry with a relation
3. Same issue with `strapi.documents('api::article.article').create()` and `strapi.documents('api::article.article').update()`

### Expected behavior

Relations in create/update should be more consistent. We should update relation with `documentId` in object, for Repeatable components, it should work as Dynamic Zone or standard collection to update Relations to be consistent.
