WIP: Add state field to tasks

What does this MR do and why?

Add Status (state) field to Create task form, can set to open / closed.

FE for #346134 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. Enable the feature

   Feature.enable(:work_items)

2. Visit issue page, add a checklist to description
3. In dropdown to the left of list item, select "Convert to task"
4. Select Closed

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.