Prevent Editor from hang when importing stl as mesh
When Importing an stl file into Godot from the import mesh menu, the
editor hangs indefinitely. Since only Obj files are supported, the data
remains unparsed and hence the editor enters an infinte loop.
This commit fixes this issue by exiting the loop when godot has finished
parsing the file, irrespective of whether any meaningful data was
extracted out.
Fixes: #9200