fix(ObjectLoader): don't validate meshes when importing obj

This should fix the broken normals.

blenderproc/python/loader/ObjectLoader.py

@@ -41,7 +41,7 @@ def load_obj(filepath: str, cached_objects: Optional[Dict[str, List[MeshObject]]
     previously_selected_objects = bpy.context.selected_objects
     if filepath.endswith(".obj"):
         # load an .obj file:
-        bpy.ops.wm.obj_import(filepath=filepath, **kwargs)
+        bpy.ops.wm.obj_import(filepath=filepath, **kwargs, validate_meshes=False)
     elif filepath.endswith(".ply"):
         PLY_TEXTURE_FILE_COMMENT = "comment TextureFile "
         model_name = os.path.basename(filepath)