NullReferenceException is thrown when resizing a text element in the UI Builder when it contains sup or sub elements and wrap mode is enabled

How to reproduce:
1. Open the attached “IN-139198“ project
2. Open the “TestLayout“ Visual Tree Asset (Assets/_Test/)
3. In the UI Builder window, resize the “Label“ element’s Width (Inlined Styles > Size) to 0
4. Observe the Console

Actual result: NullReferenceException errors are present
Expected result: No errors are present

Reproducible with: 6000.2.0a2, 6000.3.13f1, 6000.4.3f1 (39d1a88d4dd1), 6000.5.0a7
Not reproducible with: 6000.0.73f1 (3ad55a55f786), 6000.2.0a1, 6000.5.0b4, 6000.6.0a3
Fixed in: 6000.6.0a1 (b0e692525f04)

Reproducible on: Windows 10 (by user), Windows 11
Not reproducible on: No other environments tested

Note: Resizing the Label element to 0 sometimes causes the UI Builder to break, at which point it cannot be opened again until the Editor is restarted