FE: Create new related work item at group level

Release notes

You can now create new related epics directly from an existing epic, streamlining your workflow and improving your ability to manage complex projects. This new feature allows you to quickly establish connections between your work items, helping you maintain a clear overview of your project structure and dependencies.

Summary

This is the FE issue for the requirements found in #468222 (closed).

Proposal

• Add a new option to the WorkItemActions list (menu in the top-right of the page) with the label 'New related item'.
• This option should only be available if the Source Work Item has the LINKED_ITEMS widget available.
• When selected, this option should:
  • Open the CreateWorkItemModal modal.
  • The CreateWorkItem form within the modal should contain a checkbox labelled 'Relates to '. By default the checkbox should be checked.
  • When the CreateWorkItem form is submitted, the workItemCreate GraphQL mutation should be triggered using the information in the form.
    • if the 'relates to' checkbox above is checked, the gid of the source work item should be included in the payload as part of the linkedItemsWidget.workItemsIds property.
    • if not, the linkedItemsWidget property should not be included in the payload.
  • After the new item is created, a toast should appear with a link to the new item.

design reference here.