Graph delete request leaks existence of space

[C0rby]

Context

oCIS version: v2.0.0-rc.1

Issue

A user could guess space ids of spaces they don't have access to.
Since we are using uuidv4 it's improbable so this issue has a low priority.

Admin space id:

curl -k -s -u einstein:relativity -X DELETE 'https://localhost:9200/graph/v1.0/drives/1284d238-aa92-42ce-bdc4-0b0000009157$be65710a-bced-465e-9e1a-72ff269de8ee' | jq .
{
  "error": {
    "code": "notAllowed",
    "innererror": {
      "date": "2022-11-10T15:23:54Z",
      "request-id": "yocto/2IxZGOgPSg-000365"
    },
    "message": "permission denied to delete drive"
  }
}

Non existing space id:

curl -k -s -u einstein:relativity -X DELETE 'https://localhost:9200/graph/v1.0/drives/1284d238-aa92-42ce-bdc4-0b0000009157$32bdbe86-9f91-4494-8d38-49d6c0a83955' | jq .
{
  "error": {
    "code": "generalException",
    "innererror": {
      "date": "2022-11-10T15:25:31Z",
      "request-id": "yocto/2IxZGOgPSg-000369"
    },
    "message": "grpc error"
  }
}

Expected

The user should receive a generic error like "drive not found" or something like that if they can't access the drive.