The re-written header no longer shows child model objects context.

As they are not shown there is no way a user can discover the contexts from a `ModelObjectWithChildren` (https://javadoc.jenkins.io/jenkins/model/ModelObjectWithChildren.html)

this leads to non discoverable features

Steps to reproduce

• clone jenkinsci\design-library-plugin
• mvn hpi:run -Djenkins.version=-Djenkins.version=2.479.3
• go to http://localhost:8080/jenkins/design-library/links/
• In the breadcrumbs click the last `>` in the bar

Expected results

• WIth jenkins 2.479.3 the context Menu is shown with the following entries:
• Yahoo
• Google
• Microsoft
  WIth jenkins 2.508 the context Menu is shown following some new improved method to get the same menu entries/links

Actual Results

• WIth jenkins 2.479.3 the context Menu is shown with the following issues
• WIth jenkins 2.508 the context Menu there is no way (at least that is obvious) to show the child context menu.

Caused by https://github.com/jenkinsci/jenkins/pull/10245