Fix WASM tests on most recent version of ubuntu runner

[tstirrat15]

This is an example of the failure: https://github.com/authzed/zed/actions/runs/12640251291/job/35220286342?pr=447

The runner recently went from 22.04 to 24.04, and that apparently brought this change in behavior. There's some more information below:

https://chromium.googlesource.com/chromium/src/+/main/docs/security/apparmor-userns-restrictions.md

It seems like this is either an issue with the wasmbrowsertest package that we install or with the chrome instance installed on the runner; I'm hoping that enough people will run into issues with it that Github provides either official guidance or a fix.