Hide active projects from users with limited access

### Problem Statement

Hi,

We're running the self-hosted Sentry in a cloud Kubernetes environment and we've recently received a request from one of our users that they wish to invite an third party to our environment.
Requirement is that the users we invite should only be allowed to see projects they're working on, they should not be able to browse around and discover other active projects.

One thing I noticed testing this was that an user can without being a member of a team browse "Settings > Projects" and view the names of all active projects. They can't access the project, but just knowing that it exists and its name does not work for us.

### Solution Brainstorm

Would it be possible to implement something that sets a project to "private" or "hidden" in some way?

So for example, lets say we have project A, B and C.
Project B is set to "private".

Being a member of team A with access to project A will only grant me access to project A.
And browsing "Settings > Projects" would result in me only seeing project A (because I've access to this project based om my team membership) and project C (because it's not hidden).
Project B doesn't show up in the list since it's private/hidden.

A great addition to this feature would be to have another option that allowed you to implemented this as a "default" for all projects as well, just like how "Open Membership" works.

Call it "Hidden Projects" - organization members are only able to see projects they've access to.

Best regards