Android: Allow SDL_IOFromFile to open content:// URI. (#9696)

android-project/app/proguard-rules.pro

@@ -48,6 +48,7 @@
     int openURL(java.lang.String);
     int showToast(java.lang.String, int, int, int, int);
     native java.lang.String nativeGetHint(java.lang.String);
+    int openFileDescriptor(java.lang.String, java.lang.String);
 }
 
 -keep,includedescriptorclasses,allowoptimization class org.libsdl.app.HIDDeviceManager {