Don't allow interns to self assign a journey

Summary:

We don't want interns to self assign certain journeys. An intern is identified by the System person type being "Employee" and the "User Person Type" being "Intern".

I tried adding an Eligibility Profile that does not include Interns but when logging in as an Intern, I can still self-assign the Journey. So it seems this is only controlling automatic assignment based on triggers like action/action reasons and person events.

A custom role for Interns that would allow to control this template operation (under the Journey's Security tab), however this requires us to set up a lot of additional role provisioning rules, one for each User Person Type, as it is not possible to