Fix: Fixed issue that prevented using dual pane in the Column layout (#12994)

Author: hishitetsu

src/Files.App/Views/Shells/ColumnShellPage.xaml.cs

@@ -80,6 +80,8 @@ protected override void Page_Loaded(object sender, RoutedEventArgs e)
 			FilesystemViewModel.OnSelectionRequestedEvent += FilesystemViewModel_OnSelectionRequestedEvent;
 			FilesystemViewModel.GitDirectoryUpdated += FilesystemViewModel_GitDirectoryUpdated;
 
+			PaneHolder = this.FindAscendant<ColumnViewBrowser>()?.ParentShellPageInstance?.PaneHolder;
+
 			base.Page_Loaded(sender, e);
 
 			NotifyPropertyChanged(nameof(FilesystemViewModel));