Remove drop target button drawable padding if text isn't hidden

Test: manual
Fix: 194320733
Change-Id: I12adeaf37cee5a0fcf383641f24b7750f14daf27
diff --git a/res/values/dimens.xml b/res/values/dimens.xml
index 46570f0..09ac468 100644
--- a/res/values/dimens.xml
+++ b/res/values/dimens.xml
@@ -196,6 +196,7 @@
     <dimen name="drop_target_text_size">16sp</dimen>
     <dimen name="drop_target_shadow_elevation">2dp</dimen>
     <dimen name="drop_target_bar_margin_horizontal">4dp</dimen>
+    <dimen name="drop_target_button_drawable_padding">8dp</dimen>
 
     <!-- the distance an icon must be dragged before button drop targets accept it -->
     <dimen name="drag_distanceThreshold">30dp</dimen>