Unable to modify advisory votes when a large number of votes have been cast

[offbyone]

See https://glasgow-2024.sentry.io/issues/5680922867/?project=4506533834260480&query=is%3Aunresolved+issue.priority%3A%5Bhigh%2C+medium%5D&referrer=issue-stream&stream_index=0

The issue seems to be in the display of the voter table in the admin page. Each row is adding a field to the form, which eventually gets submitted, and is tripping over the DATA_UPLOAD_MAX_NUMBER_FIELDS max setting.

I don't think the right idea is to just bump the setting, but rather to change the view there to make the vote display purely that: a display, instead of a form. That'll take coding that I don't have time to do in the moment.