get preferred locales on android

(cherry picked from commit 8e22194217)

android-project/app/proguard-rules.pro

@@ -51,6 +51,8 @@
     boolean supportsRelativeMouse();
     int openFileDescriptor(java.lang.String, java.lang.String);
     boolean showFileDialog(java.lang.String[], boolean, boolean, int);
+    java.lang.String getPreferredLocales();
+    java.lang.String formatLocale(java.util.Locale);
 }
 
 -keep,includedescriptorclasses,allowoptimization class org.libsdl.app.HIDDeviceManager {