Run all CI jobs on Ubuntu 26.4 as a test

[pabzm]

Summary

• The PR was tested and verified that it works locally
• Or will be tested after merge on a dedicated test instance (available for maintainers)
• Sign-off message is added to all commits
• Tests (playwright if possible) are included
• Screenshots before/after for front-end changes
• Documentation has been updated or is not required
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone next added

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[pabzm]

Block if prerelease is present failed as expected, for this PR that is a successful run.