Redefining expanded gallery definition

[melissachen2000]

Context

The current definition of expanded galleries is hard to understand and too broad. Regarding the broadness problem, currently, if a gallery is set to "expanded" visibility mode, then all curators and creators in all of a curator's other galleries will be able to see the how-tos in this gallery. It would be more useful if the curator is able to specify which other galleries get access to this gallery's how-tos. For example, then a teacher could add Section A's gallery to Section B's gallery and vice versa, then the students can have access to each others' how-tos without having access to the projects.

Hopefully, by allowing curators to explicitly specify which other galleries get access to this one helps with the understandability of this feature, too?

Related issues

• Related Issue #
• Closes Redefine "expanded" how-to viewing permissions #1088

Verification

1. Create two users, User 1 and User 2
2. From User 1's account, create two new galleries, Gallery A and Gallery B
3. Add User 2 as a collaborator on Gallery B
4. Check that User 2 does not have access to Gallery A's gallery or how-to space
5. Change Gallery A's visibility from limited to expanded. Check that User 2 now has access to Gallery A's how-to space
6. Remove User 2 from Gallery B. Check that User 2 no longer has access to Gallery A's how-to space.
7. Add User 2 to Gallery B again. Check that User 2 has access to Gallery A's how-to space.
8. Set Gallery A to limited. Check that User 2 no longer has access to Gallery A's how-to space.
9. Set Gallery A back to expanded. Check that Gallery B is in the list of galleries granted expanded access. Check that User 2 has access to Gallery A's how-to space.
10. Delete Gallery B. Verify that User 2 does not have access to Gallery A's how-to space.

Checklist

[amyjko]

This is a nice tweak and much easier to reason about! I've done a gentle pass on the logic, and it seems sound to me.