How to reproduce:
1. Create a new empty project
2. Open the UI Builder (Window -> UI Toolkit -> UI Builder)
3. Add any element (for example, a Visual Element)
4. In the UI Builder Inspector, select any of the foldout menus
5. Try to expand or collapse it by using the left and right arrow keys
6. Observe the result

Expected result: The foldout expands/collapses
Actual result: Nothing happens

Reproducible in: 2021.3.43f1, 2022.3.44f1, 6000.0.16f1

Reproducible on: Windows 10, Windows 11
Not reproducible on: No other environments tested