Steps to reproduce:

1. Create a new URP project
2. Open Render Pipeline Converter window (Window > Rendering > Render Pipeline Converter)
3. Checkmark all options ({}Renderer and Settings Assets Setup, Material Upgrade, Animation Clip Converter and Readonly Material Converter{}) to initialize. 
4. Press Initialize Converters and quickly close Render Pipeline Converter window

Actual results: MissingReferenceException: The object of type 'UnityEditor.Rendering.Converter.RenderPipelineConvertersEditor' has been destroyed but you are still trying to access it.

Expected results: No Error is thrown

Reproducible with: 6000.4.0a2, 6000.3.0.b4, 6000.2.6f2, 6000.1.17f1, 6000.0.58f2, 2023.3.0b10, 2022.3.62f1
Not reproducible with:  -