Implement two pane widget picker

The widget picker design is currently not optimized for large screen form factor devices.
We resolve that by adding a two pane widget picker like that of the design in go/widget-picker-2023.

Bug: 256684299
Test: Make sure to be on a tablet in landscape mode.
        1.Turn on flag LARGE_SCREEN_WIDGET_PICKER.
        2. Press and hold on an empty spot in workspace until the popup menu appears.
        3. Click widgets.
        4. Notice the new two pane layout
Change-Id: Ia3ea17dc320f72f9bc5dea52399ff51d9161602b
diff --git a/res/values-sw720dp-land/dimens.xml b/res/values-sw720dp-land/dimens.xml
index 235631d..f4c4e4f 100644
--- a/res/values-sw720dp-land/dimens.xml
+++ b/res/values-sw720dp-land/dimens.xml
@@ -34,6 +34,7 @@
 
 <!-- Widget picker-->
     <dimen name="widget_list_horizontal_margin">49dp</dimen>
+    <dimen name="widget_list_horizontal_margin_large_screen">24dp</dimen>
 
 <!-- Bottom sheet-->
     <dimen name="bottom_sheet_extra_top_padding">0dp</dimen>