The search suggestion for "Group Administration" should return username instead of full name

Summary

When a group admin trying to add users into a group, they will need to search for the user beforehand.

Problem Statement

When it comes to situation where users share the same full name, it will not be easy for a group admin to distinguish between them. For example, I can two users with the full name "cc cc" in my Crowd server:

Suggestion

The suggestion should also include usernames that are unique and easily distinguishable.