Require authentication for the new work item page

/-/work_items/new answered 200 for signed-out users on public projects and rendered a stub create form that the createWorkItem mutation rejects.

Projects::IssuesController guards :new with authenticate_user!, and Groups::WorkItemsController does the equivalent in handle_new_work_item_path, but Projects::WorkItemsController never gained it. Clicking New item while signed out never opened the modal — create_work_item_modal returns before preventDefault for anonymous users, so the click followed the link. The link and that passthrough both survived the issues to work items migration; only the destination's auth filter was lost.

This restores it, so signed-out users are sent through sign-in and back to the create form with type and initialCreationContext preserved, matching /-/issues/new.

The 'issue building actions' shared example already asserted this redirect but passed for an unrelated reason: its project is private, so anonymous users were redirected by project authorization rather than by the filter. The added example uses a public project, which returned 200 before this change.

Recording

References

• #605483 (closed)
• #605427 (closed)

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