### Godot version

Master (4.2)

### System information

Windows 11 - Vulkan - Nvidia RTX 4070 - intel i5 13600KF

### Issue description

As you can see in the video when you try to add multiple scenes in to the 3D viewport (only with multiple scenes) the editor throws this error.

```
ERROR: Can't add child '@Node3D@18837' to '@SubViewport@9274', already has a parent '@SubViewport@9274'.
   at: (scene\main\node.cpp:1411)
```


Video: https://youtu.be/BVcCIigQJDw

This happens in the latest master (pulled on 2.11.2023).

### Steps to reproduce

Drag couple of the 3d mesh scenes into the 3D viewport and then select multiple scenes and drag them over and observer the error.

### Minimal reproduction project

[TestSceneDragAndDrop.zip](https://github.com/godotengine/godot/files/13253741/TestSceneDragAndDrop.zip)

_remove_preview_node();
	Vector<String> error_files;
	undo_redo->create_action(TTR("Create Node"));
	for (int i = 0; i < selected_files.size(); i++) {
		String path = selected_files[i];
		Ref<Resource> res = ResourceLoader::load(path);
		if (res.is_null()) {
			continue;
		}
		Ref<PackedScene> scene = Ref<PackedScene>(Object::cast_to<PackedScene>(*res));
		Ref<Mesh> mesh = Ref<Mesh>(Object::cast_to<Mesh>(*res));
		if (mesh != nullptr || scene != nullptr) {
			bool success = _create_instance(target_node, path, drop_pos);
			if (!success) {
				error_files.push_back(path);
			}
		}
	}
	undo_redo->commit_action();
	if (error_files.size() > 0) {
		String files_str;
		for (int i = 0; i < error_files.size(); i++) {
			files_str += error_files[i].get_file().get_basename() + ",";
		}
		files_str = files_str.substr(0, files_str.length() - 1);
		accept->set_text(vformat(TTR("Error instantiating scene from %s"), files_str.get_data()));
		accept->popup_centered();
	}
}
bool Node3DEditorViewport::can_drop_data_fw(const Point2 &p_point, const Variant &p_data, Control *p_from) {