Preventing deletion of a backup that is being actively written to

If someone has a cluster that is running a continuous backup, and they run a delete command on that backup, the delete command will erase both the existing data and the metadata that tells the list command that the backup exists. This can lead to the cluster continuing to write data into a backup that is no longer visible through the list command, effectively orphaning the backup. I think we should add a safety check to prevent deleting an active backup without providing a force flag.