Use namespace resolver query to fetch group/project work item

What does this MR do and why?

This MR changes the way we fetch a work item in both project/group level namespace.

Using a new query which uniquely identifies the work item based on iid and fullpath

Why we are doing this

A group can have multiple projects/groups within itself. Each project has a set of unique iids for work items but that is not the case for groups, Groups may have mutiple work items with the same iid from different projects.

This was causing an issue and a related issue here as well. There may be multiple more use cases that might be affected in future for the group level work items because it never caused an issue in project level issues since the set of iids is always unique.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

No UI changes before and after the query changes. All features should ideally work the same.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. GO to any work item
2. Test the following scenarios for both group and project level work items
   1. Writing a new comment
   2. Threads to an existing comment
   3. deleting a thread
   4. deleting a comment with no threads
   5. updating the todo
   6. Updating/deleting the awards
   7. Checking the activity notes/system notes with pagination
   8. Adding an emoji to a comment
   9. Actions in comments
   10. Anything else that you do with a work item