feat: add new ubuntu LTS 26.04 cloud image to container test driver

[jfroche]

No description provided.

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-09-05 21:33 UTC · Rule: default · triggered by @jfroche with the merge queue checkbox
• ❌ Checks failed · on draft merge queue: checking #537 on main (41d9628) #538
• 🚫 Left the queue — 2026-09-05 22:52 UTC · at df9a543a241b06b60cd3b295e5f70eaae7d50b4e

This pull request spent 1 hour 19 minutes 17 seconds in the queue, including 1 hour 18 minutes 51 seconds running CI.

Waiting for any of

• check-neutral = buildbot/nix-build
• check-skipped = buildbot/nix-build
• check-success = buildbot/nix-build

All conditions

• any of [🛡 GitHub repository ruleset rule main]:
  • check-neutral = buildbot/nix-build
  • check-skipped = buildbot/nix-build
  • check-success = buildbot/nix-build
• any of [🛡 GitHub repository ruleset rule main]:
  • check-success = buildbot/nix-eval
  • check-neutral = buildbot/nix-eval
  • check-skipped = buildbot/nix-eval

Reason

The merge conditions cannot be satisfied due to failing checks

• buildbot/nix-build
• buildbot/nix-eval

Failing checks:

• ❌ buildbot/nix-build

Hint

You may have to fix your CI before adding the pull request to the queue again.
If you update this pull request, to fix the CI, it will automatically be requeued once the queue conditions match again.
If you think this was a flaky issue instead, you can requeue the pull request, without updating it, by posting a @mergifyio queue comment.

Tick the box to put this pull request back in the merge queue (same as @mergifyio queue).

• Requeue this pull request