curl --request DELETE \
  --url https://api.x.com/2/activity/subscriptions/{subscription_id} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "deleted": true
  },
  "errors": [
    {
      "detail": "<string>",
      "status": 123,
      "title": "<string>",
      "type": "<string>"
    }
  ],
  "meta": {
    "total_subscriptions": 123
  }
}