Issue Summary:

With the latest updates on JSDCLOUD-1476, now agents can mention anyone in their organisation without adding them to request participants. However, for similar names customer users are being prioritized over agent users in comments on work items, if first name is used to search.
The search works fine, however, for a large customer user base (25k users), this is slightly problematic as agents have to filter through a large number of customer users to reach the agent user who is to be mentioned if they search with just first name. Hence, agent users would like to prioritise agent mentions over customer mentions with @mentions in JSM.

Steps to Reproduce

1. Ensure there are multiple customers and agent users with similar first names or perhaps entire same names (different emails)
2. On any work item use @mention. to mention a user.

Expected Results

Agent users should be prioritized over customer users in mentions on work items. This would make it easier and quicker for agent users to find and tag other agents.

Actual Results

The customer users with similar names are prioritized over agent users in the search box.

Workaround

Current workaround is to add complete names of the user in @ mentions to search effectively.