SNS：无法删除未订阅的电子邮件订阅

订阅列表（aws sns list-subscriptions-by-topic；UI 也是）显示一个可能已取消订阅的订阅的“已删除”。

{
    "Subscriptions": [
        {
            "SubscriptionArn": "Deleted",
            "Owner": "326764833890",
            "Protocol": "email",
            "Endpoint": "[email protected]",
            "TopicArn": "arn:aws:sns:us-east-1:326764833890:my-sns"
        },
        {
            "SubscriptionArn": "arn:aws:sns:us-east-1:326764833890:my-sns:65d23ee0-57e1-4ba5-86e7-2913bef8c9bf",
            "Owner": "326764833890",
            "Protocol": "email",
            "Endpoint": "[email protected]",
            "TopicArn": "arn:aws:sns:us-east-1:326764833890:my-sns"
        }
    ]
}

所以，没有什么可以用来删除的。通过 UI 删除时，它会显示错误，抱怨 ARN 只是一部分而不是六部分。