Tiny and blurry black rectangle is displayed as a placeholder when no Texture is generated

Steps to reproduce:
1. Create a new project and install the "AI Generators" package
2. Open “Generate New Texture” window (AI > Generate new > Texture)
3. Close the window and observe the placeholder for newly created Texture Asset

Actual results: Tiny and blurry black rectangle is displayed
Expected results: Black rectangle is displayed

Reproducible with versions: 1.0.0-pre.7 (6000.2.0b2), 1.0.0-pre.8 (6000.2.0b2)
Tested on (OS): macOS Sequoia 15.4 (M4)

Notes: Issue is not reproducible with Animation, Material, Sound and Sprite Assets