Comment 1 for bug 1951302

Identity-User tab is implemented in:
git/horizon/openstack_dashboard/dashboards/identity/users/tabs.py

RoleAssignmentsTab()
GroupsTab()
These tabs has parent "TableTab" then its parent is "Tab"

Tab class has function "def allowed(self, request):" to make tab invisible if this method returns "False".
But current implementation always returns "True"

By using this method "allowed", we can control tab visibility.

In upstream, it is implemented as policy_rules;

1. Introduce policy_rules
    https://review.opendev.org/c/openstack/horizon/+/775014
2. Set policy for identity
    https://review.opendev.org/c/openstack/horizon/+/783307