chore: bump Knip to 5.61.2

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 🛠 Repo: Unused files ignoreDependencies reported by Knip #5389
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Bumps Knip, then removes all unused devDependencies and unnecessary config entries. Does not remove worker.js, ref #5389

Unused files (1)
lib/nodejs/worker.js  
Unused devDependencies (1)
webpack-cli  package.json:176:6
Configuration hints (5)
Remove from ignoreDependencies: karma-chrome-launcher
Remove from ignoreDependencies: karma-mocha-reporter
Remove from ignoreDependencies: karma-mocha
Remove from ignoreDependencies: karma-sauce-launcher
Remove from ignoreDependencies: prettier

[mark-wiemer]

Updated description as this doesn't remove worker.js per #5389 . I don't want us to remove worker.js :D approved

[JoshuaKGoldberg]

The CI test failures are unrelated.