Shares drive can be shared via link share with Internal role using permissions endpoint

[saw-jan]

Describe the bug

When using the permissions endpoint, link share of Shares drive with Internal role can be created. THis should not be possible.
NOTE: with root endpoint, this is not possible.

Steps to reproduce

1. Create a link share of Shares drive with Internal role - (❗should not be possible)
   API: https://owncloud.dev/libre-graph-api/#/drives.permissions/CreateLink

curl -XPOST 'https://localhost:9200/graph/v1beta1/drives/<shares-drive-id>/items/a0ca6a90-a365-4782-871e-d44447bbc668$a0ca6a90-a365-4782-871e-d44447bbc668!a0ca6a90-a365-4782-871e-d44447bbc668/createLink' \
-d'{"type":"internal","@libre.graph.quickLink":false,"displayName":null,"expirationDateTime":null,"password":null}' \
-uadmin:admin -vk | jq

< HTTP/1.1 200 OK
{
  "createdDateTime": "2025-06-09T08:35:05.027007478Z",
  "hasPassword": false,
  "id": "RzoSVlBEeUVYUVu",
  "link": {
    "@libre.graph.displayName": "",
    "@libre.graph.quickLink": false,
    "preventsDownload": false,
    "type": "internal",
    "webUrl": "https://localhost:9200/s/xqvNlmOGVYpjjUJ"
  }
}

2. try to access the link webUrl - link doesn't work

Expected behavior

400 with error:

{
  "error": {
    "code": "invalidRequest",
    "innererror": {
      "date": "2025-06-09T08:37:41Z",
      "request-id": "sawjan-optiplex/390j8jTAqD-001876"
    },
    "message": "cannot create link on shares space root"
  }
}

Actual behavior

200 with link