Replace queryVariables with fullPath and workItemIid in work items

What does this MR do and why?

This MR cleans up work items Vue components by replacing queryVariables with fullPath and workItemIid to make props more explicit

Screenshots or screen recordings

How to set up and validate locally

1. Go to an issue and create a task in the tasks widget
2. Click on the task title to open it up in a modal (or cmd+click to open in a new window)
3. Edit the task attributes to confirm everything still works

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.