Notebook: input reports dirty even with auto save on

[bpasero]

Refs: #96279

You want to copy this behaviour over to your editor input which will hide the dirty indicator when auto save is on.

vscode/src/vs/workbench/contrib/customEditor/browser/customEditorInput.ts

Lines 121 to 131 in abb4a35

	public isSaving(): boolean {
	if (!this.isDirty()) {
	return false; // the editor needs to be dirty for being saved
	}
	if (this.filesConfigurationService.getAutoSaveMode() === AutoSaveMode.AFTER_SHORT_DELAY) {
	return true; // a short auto save is configured, treat this as being saved
	}
	return false;
	}

[rebornix]

Verifier: please validate that when auto save is set to after delay, you don't see the dirty indicator.