主体管理（创建主体）

curl --location 'kling/v1/general/advanced-custom-elements' \
--header 'Authorization: Bearer {{YOUR_API_KEY}}' \
--header 'Content-Type: application/json' \
--data '{
    "element_name": "xxx",
    "element_description": "xxx",
    "reference_type": "image_refer",
    "element_image_list": {
        "frontal_image": "xxx",
        "refer_images": [
            {
                "image_url": "xxx"
            },
            {
                "image_url": "xxx"
            }
        ]
    },
    "element_voice_id": "string",
    "callback_url": "xxx",
    "external_task_id": "",
    "tag_list": [
        {
            "tag_id": "xxx"
        }
    ]
}'