Unnecessary Line Appears Under "Imported Object" in Inspector for Input Action Asset

Steps to reproduce:

1. Create a new Unity project with the Input System package enabled
2. In the Project window, locate and select an Input Action Asset (e.g., InputSystem_Actions)
3. Observe the Inspector window

Actual results: 
A thin horizontal line appears beneath the "Imported Object" section in the Inspector

Expected Results:
No unnecessary UI lines should appear

Reproducible with versions: 2022.3.61f1, 6000.0.50f1, 6000.1.7f1, 6000.2.0b1

Tested on (OS): macOS 15.5