Recent updates to Puppeteer created issues with caching locally and
GitHub Actions. See https://github.com/hypothesis/client/pull/4887#issuecomment-1295051454.

Rather than work around this, we've decided to try and simplify our tech stack
by removing this dependency and using the system's version of Chrome to run
tests. This does introduce a risk of issues due to behavior differences between
Chrome on one system and another, but it is mature and well-tested software, and
such issues have been rare in practice. We also had this mismatch for years
when running CI on Jenkins, which used an Alpine-packaged version of Chrome.

See also Slack discussion at https://hypothes-is.slack.com/archives/C1M8NH76X/p1667826360220049.