ci: #3630066 Stop the functional testing CI job hiding composer failures

Issue: https://www.drupal.org/project/varbase_news_base/issues/3630066

composer require now fails the job after 5 failed attempts. The separate composer install is dropped: it failed all 5 attempts on every run, green ones included, because the lock no longer resolves after require -W (job 12798852). Same as varbase_search_base.

Built on !25 (merged) so the pipeline can pass. Merge !25 (merged) first, then rebase this one: only the composer commit is left.

AI-Generated: Yes

Checkpoints:

• File an issue
• Addition/Change/Update/Fix
• Testing to ensure no regression
• Automated unit testing coverage
• Automated functional testing coverage
• UX/UI designer responsibilities
• Readability
• Accessibility
• Performance
• Security
• Developer Documentation
• User Guide Documentation
• Reviewed by human
• Code review by maintainers
• Full testing and approval
• Credit contributors
• Review with the product owner
• Release notes snippet
• Release