SeekBarPreferences: adjust the margins and paddings on the dialog items.

android/res/layout/seekbar_preference.xml

@@ -2,7 +2,6 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:padding="16dp"
     android:orientation="vertical" >
 
     <TextView
@@ -10,6 +9,8 @@
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"
+        android:layout_marginTop="8dp"
+        android:layout_marginBottom="8dp"
         android:gravity="center_horizontal"
         android:textAppearance="?android:attr/textAppearanceMedium" />