Mark attachment as not accessible due to "privacy rules in Europe".

[nbartels]

There some new privacy rules in Europe and Facebook don't allows the API to access every attachment. We have to mark these attachment so it is much more easy to detect them and react.

https://developers.facebook.com/docs/messenger-platform/europe-updates

Example of the returned JSON:

"attachments": {
   "data": [
     {
       "id": "1234",
       "name": "Media not available due to new privacy rules in Europe. See developer documentation for more info"
    }
        ],
        "paging": {
          "cursors": {
            "before": "MAZDZD",
            "after": "MAZDZD"
          },
          "next": "https://graph.facebook.com/v7.0/<stuff>"
        }
      }