"NullReferenceException: Object reference not set to an instance of an object" error is thrown when attempting to remove a binding in the UIBuilder for a UxmlObjectReference

How to reproduce:
1. Open the “CommanButtonTest” project.
2. Navigate to the “CommandButtonTest.uxml” file (Assets → UI → CommandButtonTest.uxml).
3. In the UIBuilder, select “CommanButton2” from the Hierarchy
4. In the Inspector, right-click on the Command binding within the Attributes tab
5. Choose the "Remove Binding" option
6. Observe the Console window

Expected result: No error is thrown and the binding is successfully removed
Actual result: "NullReferenceException: Object reference not set to an instance of an object" appears and the binding is not removed

Reproducible with: 6000.0.49f1, 6000.1.2f1, 6000.2.0a10
Could not test with: 2022.3.62f1 (numerous unresolvable compilation errors)

Reproducible on: Windows 10, Windows 11
Not reproducible on: no other environment tested