Layer Collision Matrix header overlaps General Settings label when horizontally resizing Project Settings window

Steps to reproduce:

1. Create a new Unity project
2. Go to Edit → Project Settings
3. Select the Physics 2D section
4. Select the "Layer Collision Matrix" tab
5. Drag the middle vertical bar of the Project Settings window to horizontally resize
6. Observe the "Layer Collision Matrix"

Actual results: When resizing, the Layer Collision Matrix header label overlaps with the General Settings label

Expected results: UI labels should not overlap. The Layer Collision Matrix and General Settings headers should remain clearly separated when resizing. The minimum width must be set.

Reproducible with versions: 6000.3.0a5, 6000.3.0b1

Not reproducible with versions: 6000.0.56f1, 6000.1.16f1, 6000.2.2f1, 6000.3.0a4

Tested on (OS): macOS 15.6 M4