Update asset group (UpdateAssetGroup)

https://api.gravitex.ai/api/v3/seedance?Action=UpdateAssetGroup&Version=2024-01-01

curl -X POST "https://api.gravitex.ai/api/v3/seedance?Action=UpdateAssetGroup&Version=2024-01-01" \
  -H "Authorization: Bearer sk-your_token_key" \
  -H "Content-Type: application/json" \
  -d '{"Id": "group-20260710-abcde", "Name": "角色A-v2", "Description": "更新描述"}'

{
  "ResponseMetadata": {"Action": "UpdateAssetGroup"},
  "Result": {"Id": "group-20260710-abcde"}
}