Pass work_items_alpha for group work items

What does this MR do and why?

This MR

• enables the modal for Epic work item Child items widget
• Allows to open other Child items from the modal itself

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.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

	Before	After
Epic work item opening in a modal	Screen Recording 2024-09-09 at 7.41.02 PM.mov	Screen Recording 2024-09-09 at 6.24.27 PM.mov
Opening a Child work item from the modal	Screen Recording 2024-09-09 at 7.39.22 PM.mov	Screen Recording 2024-09-09 at 6.26.02 PM.mov

How to set up and validate locally

Prerequisites:

1. Enable the OKRs feature as mentioned in the OKRs docs (e.g. ::Feature.enabled?(:okrs_mvc, Project.find(<PROJECT_ID>)) and the namespace must have Ultimate plan).
2. Enable Epic work items
   1. Feature.enable(:work_item_epics_rollout)
   2. Feature.enable(:work_item_epics)

Steps to verify at Group level:

1. Login with any user
2. Go to Group > Epics
3. Open or create an Epic
4. Create a child item or add an existing child item
5. Click on the child item link
6. It should open in modal

Steps to verify at Project level:

1. Login with any user
2. Go to Project > Issues
3. Open or create an Issue/Objective
4. Create a child item or add an existing child item
5. Click on the child item link
6. It should open in modal
7. Create a child item or add an existing child item again from the modal
8. Click on the link of added item
9. Verify the modal is updated