Removing support for lagacy shortcuts

> Addition/removal of  shortcus is already removed. This just
  cleans up the unused code path

Bug: 275875209
Test: Updated tests
Flag: N/A
Change-Id: I8ab7f57b693f996920e50e8beecafcffab5167e9

src/com/android/launcher3/model/ModelWriter.java

@@ -498,7 +498,6 @@ public class ModelWriter {
                                 modelItem.container == Favorites.CONTAINER_HOTSEAT)) {
                     switch (modelItem.itemType) {
                         case Favorites.ITEM_TYPE_APPLICATION:
-                        case Favorites.ITEM_TYPE_SHORTCUT:
                         case Favorites.ITEM_TYPE_DEEP_SHORTCUT:
                         case Favorites.ITEM_TYPE_FOLDER:
                             if (!mBgDataModel.workspaceItems.contains(modelItem)) {