Toggling 'Editor Extension Authoring' doesn't dirty the UXML but its state depends on how it was previously saved

Steps to reproduce:

1. Create and open a new project
2. Create a new UXML and open it in UI Builder
3. Enable 'Editor Extension Authoring' on the root element
4. Add a new element to the UI Builder Hierarchy (to dirty the UXML)
5. Save the changes and close the UI Builder
6. Open the UXML again and observe the 'Editor Extension Authoring' (it should be enabled)
7. Disable 'Editor Extension Authoring'
8. Close the UI Builder (observe no 'unsaved changes' dialog box)
9. Open the UXML in UI Builder again and observe the 'Editor Extension Authoring' field

Actual results: Editor Extension Authoring is enabled

Expected results: Editor Extension Authoring is disabled

Reproducible with versions: 6000.0.0f1, 6000.0.77f1, 6000.3.18f1, 6000.4.12f1, 6000.5.0f1, 6000.6.0a7

Tested on (OS): Windows 11 Pro (25H2)