根据订阅参数获取订阅对象。
Request
GET /api/subscription/user-subscription/fetch/
Request Parameters
与subscribe接口的BODY参数相同。
Response
200
获取对象功能（即已订阅）
{
"id": 47,
"user": 7815769374283,
"followed_user": 3120595892220,
"followed_category": null,
"apply_scene": null,
"subscription_type": "follow_user",
"created_at": "2022-01-10T08:52:58.425956Z",
"updated_at": "2022-01-10T08:52:58.425387Z",
"entity_type": 100
}404
对象不存在（即未订阅）