Blog comments don't switch from old test URL to new real URL

If visiting & posting a test comment on one of one's blog pages, via a test url, say, localhost:8080, then Talkyard remembers that test url, and sends notifications with localhost:8080 instead of the blog's real address.

Original issue: Allow embedding setting messes up notification emails — but that's been resolved (a workaround). Don't want to spam Michael with notifications, so creating another.