Delete fetchByIid properties in work items

What does this MR do and why?

This MR cleans cleans up work item components by deleting fetchByIid and updating code to reflect the fact we're using IID instead of ID now

Issue: #393836 (closed)

Screenshots or screen recordings

How to set up and validate locally

1. Go to issue, create task in task widget
   1. Test opening the task from the task widget and deleting it
   2. Test removing the task from the task widget
   3. Test reordering a task in the task widget

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.