Update layout for app preference

The summary and appendix string each takes 50% of horizontal space so
they don't push the other too far off.

Change-Id: I89d859f1ec46340695aa0ef75e4c81e6435b151a
Fixes: 74028565
Test: visual

res/layout/preference_app.xml

@@ -72,9 +72,11 @@
                       android:textColor="?android:attr/textColorSecondary" />
 
             <TextView android:id="@+id/appendix"
-                      android:layout_width="wrap_content"
+                      android:layout_width="0dp"
                       android:layout_height="wrap_content"
+                      android:layout_weight="1"
                       android:textAppearance="@style/TextAppearance.Small"
+                      android:textAlignment="viewEnd"
                       android:textColor="?android:attr/textColorSecondary"
                       android:maxLines="1"
                       android:ellipsize="end" />