🛠 Repo: Stop using deprecated karma library

[mark-wiemer]

Tooling Suggestion Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
• I have read and agree to Mocha's Code of Conduct and Contributing Guidelines
• I have searched for related issues and issues with the faq label, but none matched my issue.
• I want to provide a PR to resolve this

Overview

Karma was deprecated around April 2023, and we should look at alternatives that fit our needs.

Additional Info

No response

[JoshuaKGoldberg]

Agreed. I'm personally a big fan of Playwright for end-to-end browser tests. That'd be my vote - cc @mochajs/maintenance-crew.

[voxpelli]

Yeah, playwright is what has been looked at

[JoshuaKGoldberg]

Marking as accepting PRs. Note that this is likely a big change - I would recommend only working on this once you've already done a few smaller repo tasks.