Messaging: use config_dialogCornerRadius for contacts popup

Change-Id: I320cbba61354a699e1573137483e4105ba26e461
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
diff --git a/res/drawable/popup_background.xml b/res/drawable/popup_background.xml
index 6182489..3ef00eb 100644
--- a/res/drawable/popup_background.xml
+++ b/res/drawable/popup_background.xml
@@ -17,5 +17,5 @@
 <!-- Based on the Theme.Material's default selectableItemBackground -->
 <shape xmlns:android="http://schemas.android.com/apk/res/android">
     <solid android:color="@color/contextual_action_bar_background_color"/>
-    <corners android:radius="16dp"/>
+    <corners android:radius="@*android:dimen/config_dialogCornerRadius"/>
 </shape>