Revert "Update storage_reference_ios.mm"

This reverts commit c429475.

Author: a-maurice

storage/src/ios/storage_reference_ios.mm

@@ -147,9 +147,12 @@
     future_impl->Complete(handle, kErrorUnknown, "Path cannot be empty.");
     return GetFileLastResult();
   }
-  NSURL* local_file_url = [NSURL URLWithString:path_string];
-  if (local_file_url == nil) {
-    // If it failed to load as a URL, try loading it is a path.
+  NSURL* local_file_url = nil;
+  if ([path_string hasPrefix:@"file://"]) {
+    // If it starts with the prefix, load it assuming a URL string.
+    local_file_url = [NSURL URLWithString:path_string];
+  } else {
+    // Otherwise, assume it is a file path.
     local_file_url = [NSURL fileURLWithPath:path_string];
   }
   // If we still failed to convert the path, error out.