取消消息移动任务

停止正在运行的消息移动任务；已移动的消息不会回滚。

官方英文详细说明：

Cancels a specified message movement task. A message movement can only be cancelled when the current status is RUNNING. Cancelling a message movement task does not revert the messages that have already been moved. It can only stop the messages that have not been moved yet.

This action is currently limited to supporting message redrive from dead-letter queues (DLQs) only. In this context, the source queue is the dead-letter queue (DLQ), while the destination queue can be the original source queue (from which the messages were driven to the dead-letter-queue), or a custom destination queue.

Only one active message movement task is supported per queue at any given time.