This appears to be an intermittent issue. I’ve just tried the question, and the file is where the question says it should be:
student-node ~ ➜ kubectl config use-context cluster1
Switched to context "cluster1".
student-node ~ ➜ ssh cluster1-controlplane
Welcome to Ubuntu 22.04.4 LTS (GNU/Linux 5.4.0-1106-gcp x86_64)
* Documentation: https://help.ubuntu.com
* Management: https://landscape.canonical.com
* Support: https://ubuntu.com/pro
This system has been minimized by removing packages and content that are
not required on a system that users do not log into.
To restore this content, you can run the 'unminimize' command.
cluster1-controlplane ~ ➜ ls /opt
cluster1_backup_to_restore.db cni containerd kubernetes-metrics-server
This happens occasionally; for whatever reason, the question setup script fails, and an asset you need for a question fails to be provisioned. This appears to have happened to you here.
Sorry about that. But if you try the question again, it should work for you, most likely.