window/Edit: read digest also from top level response

we want to have the digest in the top level object, like:
{
    data: { /* the real data */ },
    digest: "fa123asf123123123", // the digest
}

instead of in the data itself, so read it preferably from there
(with fallback to stay compatible)

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>