iOS: if the file doesn't exist in the pref path, use the current directory

Fixes https://github.com/libsdl-org/SDL/issues/14743

src/io/SDL_iostream.c

@@ -985,6 +985,10 @@ SDL_IOStream *SDL_IOFromFile(const char *file, const char *mode)
 
         fp = fopen(path, mode);
         SDL_free(path);
+
+        if (!fp) {
+            fp = fopen(file, mode);
+        }
     }
 
     if (!fp) {