Issue visibility not honored for groups

Summary

Setting visibility of issues on a public repository to "Only team members" does not fully hide the issues if the repository is in a group, since they will be visible on the group page (which is public).

Example:

Repository with issues not visible: https://gitlab.com/kada-development/SmsServer-app

Group page, issues are visible (although not accessable): https://gitlab.com/groups/kada-development/issues

Steps to reproduce

1. Set issues visibility to "Team members only" in a group owned repository
2. Go to the (public) page for the group owning the repository.

Expected behavior

Issues are not visible

Actual behavior

Issues are visible

Possible fixes

(If you can, link to the line of code that might be responsible for the problem)