Sorry, this was because I was testing on my admin account which does not need a confirmation.
However, I also tested on a different account and the email arrived properly:
In reply to Paul Greidanus
Re: Moodle.org not sending email to confirm email change [Solved]
by Helen Foster -
Update: I don't know what changed, but it seems that moodle.org email change confirmation emails are now being sent. I received one almost immediately.