Update drop target styling based for BC.

Spec: https://docs.google.com/presentation/d/1UxdDh8EFhPbdRWRwzjbpgL-j02ew4Ew3eG3XBCeoYdo/edit#slide=id.vXfwHn8

Demo: https://drive.google.com/file/d/1ZIa3Dgo85vdVkfPm7aGJDyctZQR_c8Xx/view?usp=sharing

Test: manual
Bug: 184713740
Change-Id: I17dbbf1f7bbc40939cfc0fedb506a35f39ecc2e3
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 600a550..dd14eaa 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -158,7 +158,7 @@
 <!-- Dragging -->
     <!-- Drag padding to add to the bottom of drop targets -->
     <dimen name="drop_target_drag_padding">14dp</dimen>
-    <dimen name="drop_target_text_size">14sp</dimen>
+    <dimen name="drop_target_text_size">20sp</dimen>
     <dimen name="drop_target_shadow_elevation">2dp</dimen>
 
     <!-- the distance an icon must be dragged before button drop targets accept it -->