Adding a carent in the scrim

> Caret is only visible when the accessibility is enabled
> It is visible in NOTMAL and OVERVIEW state and moves out of the
  scrim along with the scrim.
> Acts as an accessible target for various options

Bug: 78172350
Bug: 79215734
Change-Id: I8a968b67e36901859649546295f6491d49cc9ce9
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index b1ad11e..cd050e8 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -42,6 +42,7 @@
     <dimen name="all_apps_scrim_radius">8dp</dimen>
     <dimen name="all_apps_scrim_margin">8dp</dimen>
     <dimen name="all_apps_scrim_blur">4dp</dimen>
+    <dimen name="vertical_drag_handle_size">24dp</dimen>
 
 <!-- Drop target bar -->
     <dimen name="dynamic_grid_drop_target_size">48dp</dimen>