Bring born-digital MVP out from toggle

[rcantin-w]

As part of removing the toggle, we have a few pieces that have come out that are not blockers, but need doing once we're happy with the work. They weren't officially part of the epic, so listing them here as to not be forgotten. Feel free to add more:

To do

• [x] https://github.com/wellcomecollection/wellcomecollection.org/issues/11065

• [ ] Remove cookie from test

[pollecuttn]

https://github.com/wellcomecollection/wellcomecollection.org/issues/11016 is a blocker to born digital being released

[rcantin-w]

I'll move this back to the backlog as this should be done once we're actually removing the toggle and tidying up the codebase. For now, we just set the toggle's public status to ON.