Add client side routing to group work items

What does this MR do and why?

This MR adds client-side routing for group-level work items list. Please note that client navigation will only be triggered if the work item is a direct child of the group: currently, only epics are direct children of the group so we can observe client routing on the epics list.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

1. In rails console enable the following feature flags

   Feature.enable(:namespace_level_work_items)
   Feature.enable(:work_item_epics_list)

2. Visit group epics route: http://127.0.0.1:3000/groups/flightjs/-/epics/
3. Try clicking on epics, browser's Back and breadcrumbs