Profile picture macro `view user profile` button is broken

Issue Summary

Profile picture macro tooltip button `view user profile` doesn't work.

Steps to Reproduce

1. Insert a profile picture macro
2. hover the macro in editor 
3. click `view user profile` button

Expected Results

it should go to the user profile page like `~/display/~zac`

Actual Results

it goes to `~/display/~undefined` 

Workaround

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

Findings

This has been broken for 9 years due to letter case change. It seems no one really uses this button.
https://bitbucket.org/atlassian/confluence-profile-picture-plugin/commits/2265bf4