The file key of a FileBone relation is being sent to the viur-core under a wrong form-key

[sveneberth]

I have a file relation like:

    image = FileBone(
        descr="Image",
        derive={
            "thumbnail": [
                {"width": 200, "height": 200},
                {"width": 400, "height": 400},
            ],
        },
    )

The file relation (the file key) is not sent correctly to the viur-core in an skeleton edit.

It sends my_image_bone.key, but not my_image_bone -- but this is what the core currently expects (without an using skel). Therefore, the value is not practically submitted and not written in the Skeleton. Even if the preview is kept after saving, the supposedly set image is gone again after a reload.

This bug is related to viur-framework/viur-core#1045

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Payload of an existing file entry (invalid; without image):

image.key: ag12aXVyMy1*************gRmaWxlGICAgNj1mIUKDA
image.creationdate: 2023-05-12T18:30:11+02:00
image.changedate: 2023-05-12T18:30:11+02:00
image.viurCurrentSeoKeys.en: 565***1987200
image.parententry: ag12aXVyMy1************ROb2RlIg9yZXBfbW9kdWxlX3JlcG8M
image.parentrepo: ag12aXVyMy10*************b3ROb2RlIg9yZXBfbW9kdWxlX3JlcG8M
image.sortindex: 1683909011.347819
image.size: 4166
image.dlkey: 01***iCFI
image.name: super_cloud.png
image.mimetype: image/png
image.weak: false
image.pending: false
image.width: 0
image.height: 0
image.downloadUrl: /file/download/MDF**FpOd****Y2Uvc3VwZXJfY2xvdWQ*ADAA?sig=a437f14e8fe61e9874c03ded******d59cca764d15813c24f1a247**ba939bb2f7c2757ac07
image.derived: 
image.pendingparententry: ag12aXVy**************XBfbW9kdWxlX3JlcG8

Payload of an directly uploaded file (correctly; with image):

image: ag12aXVy**********ICAgLjgmo0JDA
image.key: ag12aX*********ELEgRmaWxlGICAgLjgmo0JDA
image.rel: 

---

Using:

vi-admin: v4.1.3
viur-core: v3.5.14