The service desk e-mail is public if the issue tracker is public

Summary

The service desk e-mail is public if the issue tracker is public

Steps to reproduce

• Enable service desk
• Make the issue tracker available for anyone
• In a browser window not logged into gitlab, navigate to the repo, issues then service desk
• The page says: "Have your users email redacted@incoming.gitlab.com*

Example Project

https://gitlab.com/zerodogg/gitlab-issue-service-desk-public/issues/service_desk

What is the current bug behavior?

E-mail is publicly displayed.

What is the expected correct behavior?

The e-mail shouldn't be publicly displayed. The documentation for service desk states "We recommend putting this behind an alias so that it can be changed if needed". This can't be done since gitlab itself publicizes the address to everyone (at least not without making the entire issue feature private).