Resolve "Use IID + full path for Tasks"

What does this MR do and why?

This MR implements the frontend part for fetching and displaying work items by iid instead of global id. The reason for this change is that currently we display work items at :grou[/:project/work_items/:id route where id is global, and the work item with this ID can belong to a completely different group or project. With iid, we always fetch the work item relative to the current project.

Screenshots or screen recordings

Work item fetched by global id	Work item fetched via :iid

How to set up and validate locally

1. Enable fetching work items via iid

    Feature.enable(:use_iid_in_work_items_path)

2. Open work item with iid_path query parameter: http://127.0.0.1:3000/flightjs/Flight/-/work_items/1?iid_path=true
3. Check the core WI functionality: creating a work item, updating widgets, realtime updates

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #372886 (closed)