Divider line is missing in "AI Model" window

Steps to reproduce:

1. Create a new project and install the "AI Generators" package
2. In the Project window, right-click -> Create -> 2D -> Generate Sprite
3. Press "Change" button to select AI Model
4. Observe the window

Actual results: Divider line is missing between settings and AI Models

Expected results:  Divider line is not missing between settings and AI Models

Reproducible with versions: AI Generators 1.0.0-pre.6 (6000.2.0a10)

Tested on (OS):  Windows 11