v2.8.21-canary.4

<!-- Release notes generated using configuration in .github/release.yml at v2.8.21-canary.4 -->

What's Changed

Changelog

• chore: Upgrade Next.js by @anthonyshew in https://github.com/vercel/turborepo/pull/12415
• Revert "fix: Flush stale mouse tracking events from stdin during TUI cleanup" by @anthonyshew in https://github.com/vercel/turborepo/pull/12416

Full Changelog: https://github.com/vercel/turborepo/compare/v2.8.21-canary.3...v2.8.21-canary.4