ci: fix running tests in Ubuntu 24.04

Ubuntu 24.04 has stricter AppArmor policies that prevent Puppeteer from
running, with an error like:

> Failed to launch the browser process!
> [0109/235031.343250:FATAL:zygote_host_impl_linux.cc(128)] No usable sandbox! If you are running on Ubuntu 23.10+ or another Linux distro that has disabled unprivileged user namespaces with AppArmor, see https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md. Otherwise see https://chromium.googlesource.com/chromium/src/+/main/docs/linux/suid_sandbox_development.md for more information on developing with the (older) SUID sandbox. If you want to live dangerously and need an immediate workaround, you can try using --no-sandbox.

We can use [`aa-exec`][1] to explicitly set the `chrome` policy and get
it working again.

[1]: https://manpages.ubuntu.com/manpages/noble/man1/aa-exec.1.html
See: #730 (comment)

.github/workflows/test.yml

@@ -22,4 +22,4 @@ jobs:
       # throws an error if package-lock.json is out-of-date
       - run: npm ci
       # runs jest unittests
-      - run: npm test
+      - run: aa-exec --profile=chrome npm test