WebGL plugin throws exception when entering the Play Mode while the plugin is open in the Inspector window

Reproduction steps:
1. Open the attached “BugRepro” project
2. Open the “Scenes/SampleScene” Scene
3. Select the “Assets/test.jslib” Asset in the Project window to open it in the Inspector window
4. Enter the Play Mode
5. Observe the Console window

Expected result: No exceptions are printed out
Actual result: Multiple exceptions of the same type are printed out: The type initializer for 'UnityEditor.Scripting.ScriptCompilation.CustomScriptAssembly' threw an exception.

Reproducible with: 6000.0.1f1, 6000.0.3f1
Not reproducible with: 2021.3.39f1, 2022.3.31f1, 6000.0.0f1
Fixed in: 6000.0.4f1

Reproducible on: Windows 10
Not reproducible on: No other environment tested