Fixed flipped scene preview thumbnail

No need to flip the image generated from the viewport texture anymore.

editor/editor_node.cpp

@@ -1172,8 +1172,6 @@ void EditorNode::_save_scene_with_preview(String p_file, int p_idx) {
 			}
 			img->convert(Image::FORMAT_RGB8);
 
-			img->flip_y();
-
 			//save thumbnail directly, as thumbnailer may not update due to actual scene not changing md5
 			String temp_path = EditorSettings::get_singleton()->get_cache_dir();
 			String cache_base = ProjectSettings::get_singleton()->globalize_path(p_file).md5_text();