Org-owned projects: Cannot remove yourself as Sole Owner

[webknjaz]

Describe the bug

It looks like Warehouse gets confused when an org owner looks into the Collaborators page of a project that is also owned by that same org, it thinks that the logged in owner shouldn't be allowed to be deleted.
It's possible to change other users from Owners to Maintainers and back, but not oneself. Even when that other account is the only one in the list (except for the org).

Expected behavior

The PyPI shouldn't think that the currently logged in user is the sole owner of a project when it's owned by the org. It should also allow changing oneself from Owner to Maintainer in the UI (it's currently inactive).

To Reproduce

1. I've gone to https://pypi.org/manage/project/yarl/collaboration/
2. Saw myself listed as an owner (plus another person as a maintainer), and the project is org-owned
3. I clicked Remove and it errored out with Cannot remove yourself as Sole Owner

My Platform

N/A

Additional context