How to reproduce:
1. Create a new 3D URP Sample project and open the "TerminalScene" scene
2. Go to Window -> Analysis -> Rendering Debugger -> Volume
3. Open the "Camera" dropdown
4. Observe the dropdown options
Expected results: The is no "None" option
Actual results: There is "None" option that can't be selected
Reproducible with: 6000.2.0a4, 6000.2.1f1, 6000.3.0b1
Not reproducible with: 6000.0.57f1, 6000.2.0a3
Reproducible on: macOS Sequoia 15.6 (M1), Ubuntu 24
Not reproducible on: No other environment tested