How to reproduce:
1. Create a new Unity project
2. Open Window -> UI Toolkit -> Samples
3. Open any Section and narrow down the window so part of the code or text is not visible
4. Observe the window
Expected results: There is a horizontal scrollbar since not all content can't fit in the window
Actual results: There is no horizontal scrollbar even though not all content can fit in the window
Reproducible with: 2021.3.40f1, 2022.3.39f1, 6000.0.12f1
Reproducible on: Windows 11 (ARM), macOS Sonoma 14.5 (M1)