Make AVDC sample drawable larger

Makes it easier to see

Change-Id: Ied27b97481d9d523e6410d6769229b3abb10c14f
diff --git a/samples/Support7Demos/res/drawable/vector_drawable_grouping_1.xml b/samples/Support7Demos/res/drawable/vector_drawable_grouping_1.xml
index b4f428c..543d934 100644
--- a/samples/Support7Demos/res/drawable/vector_drawable_grouping_1.xml
+++ b/samples/Support7Demos/res/drawable/vector_drawable_grouping_1.xml
@@ -14,8 +14,8 @@
      limitations under the License.
 -->
 <vector xmlns:android="http://schemas.android.com/apk/res/android"
-        android:height="64dp"
-        android:width="64dp"
+        android:height="256dp"
+        android:width="256dp"
         android:viewportHeight="256"
         android:viewportWidth="256">