Support RTL context for Cellbroadcast Settings.

Bug: 29155522
Change-Id: I47a2eb90abd143eb7eae813fc5b5fb4ae2c28fa0
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 228954c..18413e4 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -36,6 +36,7 @@
             android:icon="@mipmap/ic_launcher_cell_broadcast"
             android:backupAgent="CellBroadcastBackupAgent"
             android:defaultToDeviceProtectedStorage="true"
+            android:supportsRtl="true"
             android:directBootAware="true">
 
         <meta-data android:name="com.google.android.backup.api_key"