Enabling or Disabling UI Toolkit Live Reload for Import Activity window throws a Window serialization error

Steps to reproduce:

1. Create a new project
2. Open the Import Activity window (Window -> Analysis -> Import Activity)
3. Right-Click on the Window handle
4. Select the option to enable/disable UI Toolkit Live Reload 

Actual results: A window serialisation error is thrown every time the option is enabled/disabled

Expected results: No errors or warnings are thrown when enabling/disabling the UI Toolkit Live Reload option for the Import Activity window

Reproducible with versions: 6000.0.82f1, 6000.3.22f1, 6000.5.9f1, 6000.6.0b9, 6000.7.0a5

Tested on (OS): Ubuntu 24, macOS 26.5.2

Full error message:

• Window serialization will fail for UnityEditor.ImportActivityWindow, will not reload it. Make sure that there are no compile errors and that the file name and class name match.
  UnityEditor.RetainedMode:UpdateSchedulers () (at /Users/bokken/build/output/unity/unity/Modules/UIElementsEditor/RetainedMode.cs:47)