Display name of a deleted user is still visible via REST API

Issue Summary

If a user is removed from a Jira site, their display name is still visible for the other users if they query the /rest/api/3/users endooint

Steps to Reproduce

1. Invite a user to a Jira site
2. Remove that user from the site

Expected Results

The user's personal information (display name) should not be returned anymore, since the user is no longer part of the site

Actual Results

The display name is still return.

This is an issue because anyone in a Jira site (that has the browse users and groups permission) can see the names of anyone that have ever been in that particular site

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available