I have no idea why this is flaking. There are warnings about
things not being wrapped in act() which may be relevant... this makes
the warnings happy, although apparently should not be necessary.
https://github.com/testing-library/user-event/discussions/906 and
https://github.com/testing-library/user-event/issues/497 are
depressing reading (making the versions the same didn't help). I think
my conclusion might be to do this until we're able to upgrade to the
latest testing-library, then re-evaluate.
It still may or may not fix the flake.
9aa09d4b15