R1:2c626f72a9ef

Fix unsubscribing from projects in a gross, hacky way

Summary:
Fixes T5261.

This fix isn't very good. Two better fixes would be:

# Add some sort of `setRole(SUBSCRIPTIONS)` method to `ObjectQuery`, which gets passed down until it reaches `ProjectQuery`, and `ProjectQuery` knows that it needs to load more data. This feels OK, but is a very general approach and I don't think we have many/any other use cases right now. I //think// this is the right way in the long run, but I'd like to have more use cases…