Apparently moving forward, https://wikimania.wikimedia.org will be used for all future Wikimanias. Since it is not a temporary wiki, it may make sense to add it to the pageviews API.
This is not only not in the whitelist, it's excluded from the pageview definition. The logic was that we don't want to include traffic to wikis that are not about "content". I believe we made an exception for outreach wiki, so we have to talk about whether we want to just allow all wikis.