Create task immediately and switch to edit mode

What does this MR do and why?

1. Change 'Convert to work item' button tooltip to say 'Create task'
2. Clicking button creates a task instantly, then opens the detail modal
3. Deleted most of the isModal stuff from create_work_item.vue (since we don't need it anymore)
4. Add 'Task' label (or other work item type) to the top of work item detail
5. Move Status field to top of the form
6. Even up alignment/spacing of the fields on work item detail
7. Remove borders from description
8. Edit button is now just an icon
9. Move save/cancel buttons to below description
10. Add empty state to description

Screenshots or screen recordings

Screen_Recording_2022-06-20_at_8.36.33_pm

How to set up and validate locally

1. Enable the work_items feature flag

   Feature.enable(:work_items)

2. Visit any group or project issue page, add a checklist to issue description
3. Hover a checklist item, click "Convert to task"
4. Task is created, Modal opens in edit view

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.