NullReferenceException is thrown when assigning PanelSettings asset to a UIDocument dynamically at runtime

Reproduction steps:
1. Open the attached “IN-96904.zip” project
2. Open the “SampleScene”
3. Enter the Play mode
4. Observe the Console

Expected result: No errors
Actual result: “NullReferenceException: Object reference not set to an instance of an object” is thrown

Reproducible with: 2023.2.0a9, 6000.0.41f1, 6000.1.0b11, 6000.2.0a7
Not reproducible with: 2022.3.59f1, 2023.2.0a8

Reproducible on: Windows 11
Not reproducible on: No other environment tested