[JENKINS-74871] Fix the broken jelly view

[yaroslavafenkin]

I've messed up the index.jelly view in #146, causing https://issues.jenkins.io/browse/JENKINS-74871.

Testing done

Followed the steps in the JIRA ticket for manual tests. Added automated test that fails before the fix and passes after the fix.

Submitter checklist

• Make sure you are opening from a topic/feature/bugfix branch (right side) and not your main branch!
• Ensure that the pull request title represents the desired changelog entry
• Please describe what you did
• Link to relevant issues in GitHub or Jira
• Link to relevant pull requests, esp. upstream and downstream changes
• Ensure you have provided tests - that demonstrates feature works or fixes the issue