Collection doesn't show available Viewports for anonymous users when there is a versioned space in the collection without marked versions available for Viewport

Steps to reproduce

1. Create 3 spaces: A, B & C.

2. Create a Viewport collection with A being the root space and B&C being members.

3. Activate Scroll Versions in space B. Do not make any versions available in Viewport on the Versions screen.

4. Make all of the spaces available for anonymous users.

5. Try to access any of the viewports in an anonymous tab.

Expected result

Viewports A&C are accessible to anonymous users, viewport B is not. 

Actual result

All of the viewports fail to display. See error in attachment.