fix when the TreeListView expands too much content, scrolling to the …

[MohammadHadi2031]

…top will shrink the content #3640

Hi Keboo. I think we can fix this with easy trick. I get IsExpanded from itemsSource.GetIsExpanded(index) to PrepareTreeListViewItem OnApplyTemplate. Always PrepareTreeListViewItem is called twice from PrepareContainerForItemOverride and OnApplyTemplate so we can remove PrepareContainerForItemOverride in TreeListView but that is optional. Calling PrepareTreeListViewItem once was not the solution since ItemExpandedChanged was called multiple times causes items to be added twice so it should be changed to have no effect when IsExpanded was not changed actually.