Load provided demo data

[Ke-Wang1017]

Hi after realizing that data generated by script is mostly fail #12 , i use the demo data provided by the author. However I ran into data loading error when running the 'sim_transfer_cube_scripted' task. But you can remove 'left_wrist' and 'right_wrist' at https://github.com/MarkFzp/act-plus-plus/blob/main/constants.py#L11 and data can load successfully. Hope that helps :)