Download body motion from the json file

[jiaoc1]

In the download_urls.json, the key for body motion is "body_motion". It doesn't match the DataGroups name "body" in line 126 in the definition.py. Therefore, the DownloadManager cannot find the download link in line 223 in download_utils.py. Could you please either update the DataGroups by changing the "body" to "body_motion" or update the "body_motion" to "body" in the json file to fix the issue?