secondary-window: Respect autoSave

[lucas-koehler]

Feature Description:

The issue tracks a known limitation from #11048 that webviews (esp. custom editors) in secondary windows do not respect the autoSave option.

Steps to Reproduce:

1. start the browser-app with the custom-editor-sample extension
2. start the application with exampleFiles as a workspace
3. ensure that autoSave is off
4. open example.cscratch
5. add/remove entries in the file - confirm the file is dirty and closing the file prompts users
6. open example.cscratch in a secondary window
7. add/remove entries in the file - no visual indicator that the file is dirty
8. attempt to close the dirty window - the window is closed, and a dialog appears after the fact in the main window (related secondary-window: Open dialogs in the secondary window #11647)
9. if you use cancel in the dialog the file can never be re-opened unless the app is restarted.

Screen.Recording.2022-09-19.at.8.12.17.AM.mov

[tsmaeder]

@lucas-koehler by "respecting autosave" you mean that there is no dialog asking to save when the editor is closed when dirty? If so, this is a problem that existed before.

[lucas-koehler]

I believe this was discovered by vince and means that the auto save was not executed after a change.
@vince-fugnitto Do you remember details on this, i.e. what didn't work and which extension you used when discovering this?

[vince-fugnitto]

@lucas-koehler @tsmaeder I updated the pr with additional steps to reproduce the bug.

[tsmaeder]

Done as part of #11642