Duplication of products no longer works

### Shopware Version

6.6.10.25

### Affected area / extension

Platform(Default)

### Actual behaviour

When duplicating a product via the `Save and Duplicate` button in the administration backend, nothing
happens. The request fails with:
```
{
"errors": [
{
"status": "400",
"code": "FRAMEWORK__WRITE_CONSTRAINT_VIOLATION",
"detail": "This field is write-protected. (Got: \"crud\" scope and \"system\" is required)",
"source": {
"pointer": "/childCountchildCount"
},
"meta": {
"parameters": [
"crud",
"system"
]
}
}
]
}
```

The request sent by the system is:

```
{
"cloneChildren": false,
"overwrites": {
"active": false,
"childCount": 0,
"mainVariantId": null,
"name": "EVA Foam Tape 5mm wide, 3mm thick, 4m length Kopie",
"productNumber": "RT10231",
"variantListingConfig": {
"configuratorGroupConfig": null,
"displayParent": null,
"extensions": [],
"mainVariantId": null
}
}
}
```

### Expected behaviour

The product is duplicated, as it worked in previous versions

### How to reproduce

- Edit any product, choose `Save and duplicate`