How to reproduce:
1. Open the attached project "Reproduction"
2. Open the "Assets -> Scenes -> EnemiesShowcase" scene
3. Make sure the Unity Version Control tab is opened
4. Enter the Play Mode
5. Observe the Console

Expected results: No errors are thrown 
Actual results: NullReferenceException is thrown

Reproducible with: 2022.3.56f1, 6000.0.34f1, 6000.1.0b2

Reproducible on: macOS Sequoia 15.1 (M1)
Not reproducible on: No other environment tested

Notes:
- Unity Version Control window doesn't need to be focused or active to throw errors
- After reopening the project or Version Control window, errors usually appear after the second time entering the Play Mode
- After errors are thrown on entering the Play Mode, the same error is thrown when closing the Unity Version Control window

Full error:
NullReferenceException: Object reference not set to an instance of an object
Unity.PlasticSCM.Editor.ViewSwitcher.OnDisable () (at ./Library/PackageCache/com.unity.collab-proxy@2.6.0/Editor/ViewSwitcher.cs:205)
Unity.PlasticSCM.Editor.PlasticWindow.ClosePlastic (Unity.PlasticSCM.Editor.PlasticWindow window) (at ./Library/PackageCache/com.unity.collab-proxy@2.6.0/Editor/PlasticWindow.cs:1096)
Unity.PlasticSCM.Editor.PlasticWindow.OnDisable () (at ./Library/PackageCache/com.unity.collab-proxy@2.6.0/Editor/PlasticWindow.cs:283)