appDisplay: Set minimum folder view rows to 1

This improves the usage of empty space in the dialog.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/896

js/ui/appDisplay.js

@@ -1283,6 +1283,8 @@ class FolderView extends BaseAppView {
             layout_manager: new Clutter.BinLayout(),
             x_expand: true,
             y_expand: true,
+        }, {
+            minRows: 1,
         });
 
         // If it not expand, the parent doesn't take into account its preferred_width when allocating