Explicitly export content providers

In a future version of Android, the default value for
<provider android:exported> will change from true to false.
Explicitly set android:exported="true"

Bug: 3306452

Change-Id: Iffe4dca4fefc92bb9f89698f149a87c16a7ce3c5

packages/SettingsProvider/AndroidManifest.xml

@@ -14,6 +14,7 @@
 
         <provider android:name="SettingsProvider" android:authorities="settings"
                   android:multiprocess="false"
+                  android:exported="true"
                   android:writePermission="android.permission.WRITE_SETTINGS"
                   android:initOrder="100" />
     </application>