ci: use ubuntu-22.04

[h-a-n-a]

Summary

ubuntu-latest is rolling out with ubuntu-24. Latest glibc versions are no longer supported on older systems.

Downgrade ubuntu-latest to ubuntu-22.04 to make it compatible with playwright docker jammy. I didn't choose
to upgrade playwright docker as it makes us dropping the support for older glibc versions. This is not acceptable.

Ref: actions/runner-images#10636

Failing CI: https://github.com/web-infra-dev/rspack/actions/runs/12408927487/job/3464188805

This is also related to this PR switching us from self-hosted runner to GitHub runner: #7243

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[netlify]

✅ Deploy Preview for rspack canceled.

Name	Link
🔨 Latest commit	20d42ea
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[codspeed-hq]

CodSpeed Performance Report

Merging #8776 will not alter performance

_{Comparing h-a-n-a:ci-ubuntu (20d42ea) with main (0e749f0)}

Summary

✅ 1 untouched benchmarks