Alt+click on List header does not recursively toggle child foldouts when items use a UI Toolkit CustomPropertyDrawer

Steps to reproduce:
1. Open the attached “IN-145980” project
2. Open the SampleScene
3. In the Hierarchy Tab select the GameObject named “TEST”
4. In the Inspector Tab click the “Items” header while holding Alt
5. Observe the Inspector

Actual Result: Only the outer list foldout collapses/expands
Expected Result: Alt+clicking the list header should recursively collapse/expand all child Foldouts inside the list, matching the standard Unity Inspector behavior

Reproducible with: 6000.0.0f1, 6000.0.78f1, 6000.3.18f1, 6000.5.1f1, 6000.6.0b1, 6000.7.0a1

Reproducible on: macOS 26.5 (M1), Windows 11 (by reporter)
Not reproducible on: No other environments tested

Note: When CustomPropertyDrawer is not used Alt+click works as intended