Improvement to sync user's latest username in history tab

Description

When a issue is assigned to a user, the history tab record the user display name and username. However, when the user changed the username, JIRA issue history tab seems to still using the old username to record the users action.

Step to reproduce

1. Create a user(lets say 'test') and using the user, perform certain actions on any issue (like adding issue links, comments etc)
2. Notice that the issue history tab shows changes made by this user 'test'.
3. Now rename this user from administration console giving it a new username (say 'testabc').
4. Now make some more changes to the issue using this renamed user.
5. Now go to the history tab and notice that the old username 'test' is still being used. The new username 'testabc' is never used in the history tab.

Suggestion

• Update the user's username from the old to the latest in history tab, or
• Remove IDs of the fields value in the history tab