test-list: add entry endpoint not working

[hellais]

There seems to be an issue with the endpoint for adding new entries to the URL priorities.

When I attempt to add a new priority rule I get the following error:

The payload of the request is to https://api.ooni.org/api/_/url-priorities/update is the following:

{"old_entry":{},"new_entry":{"category_code":"*","cc":"KZ","domain":"www.azattyq.org","url":"*","priority":9999}}

While the response is the following:

{
    "detail": [
        {
            "type": "missing",
            "loc": [
                "body",
                "old_entry",
                "priority"
            ],
            "msg": "Field required",
            "input": {},
            "url": "https://errors.pydantic.dev/2.12/v/missing"
        }
    ]
}

[aagbsn]

does it return 422 unprocessable entity? I think the issue is that old_entry is not None; I changed the UI frontend ooni/test-lists-ui#84 to do this; maybe this needs to apply to the admin view as well