OKR for GitLab: Add support for showing Objective and Key Result as a child item within tree view
Summary
Once we have #381848 (closed) addressed, we need to add support for showing Objective and Key Result as a child item within tree view, which includes showing items with appropriate type icon, progress information, as well as status labels.
The designs for this component are available in #381118[Objective_view_full.png]