When a request for GetProfilePicThumb fails, WhatsApp sends an JSON object
containing a status field: `{"status":404}`. In my tests, it did send the
codes 401 and 404 which might correspond to the HTTP status codes. At
least, we don't have data to update the avatar and should stop doing so.
When a request for GroupMetadata fails, WhatsApp sends an JSON object
containing a status field: `{"status":500}`. In my tests, it sends the
codes 401, 404 and 500 which might have the meaning of the HTTP status
codes. At least, we don't have data to update the portal and should stop
doing anything.
