Relation error when linking media with document service
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## Bug report

### Required System information

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- Node.js version: v22.11.0
- NPM version: 10.9.0
- Strapi version: 5.4.1
- Database: Postgres
- Operating system: MacOS Sequoia 
- Is your project Javascript or Typescript: TS

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### Describe the bug

When updating a document using the documents service, media document IDs throw an error:

`ValidationError: Invalid relations`

Using the media ID instead of the document ID doesn't throw an error but it doesn't link the asset.

### Steps to reproduce the behavior

Update or create a document with a media field (the media field is for single media so I'm not using {set: ...}
Example data:

```json
{
  "publishedAt": null,
  "variants": { "set": ["yppiqj4yyx0f5ll9inw0vj5n", "xrtmvkz2rzmioxfh6d42z9nc"] },
  "images": [
    { "colours": { "set": ["sbz6n29rfvyei79cm7afzdla"] }, "thumbnail": "t9pt1v954eranjz3purhuz42" },
    { "colours": { "set": ["sbz6n29rfvyei79cm7afzdla"] }, "thumbnail": "t9pt1v954eranjz3purhuz42" }
  ],
  "brand": "m5jqije2vcjj1mf8euicao8n",
  "season": "e30xzoyfotde0a8rbyq3fd6h",
  "description": [],
  "categories": {
    "set": ["bfeadw4oz449gc95vgg0gric", "mnddaru6f5uq3f1oiin8sgls", "rjdrs0zvlz2vh63nhob8uu9s"]
  }
}
```

### Expected behavior

I'd expect the media relations to work the same as normal relations
