Revert "Fixed Bok-Choy test (wrong selector)"

This reverts commit 2bb9dd05b66c0925cd057206d19210f5f7569897.
Use set instead lists.
TNL-660: Toggle single note visibility.
Fix rebase conflicts.
Merge pull request #5896 from edx/anton/toggle-single-note

TNL-660: Toggle single note visibility.