bug(coderd_template): doesn't cancel template builds mid-update

Not sure if this is intended, but when cancelling a Terraform job during a template update (e.g. ctrl+C), it doesn't try to also cancel the template version that's in mid-flight. More specifically, I was expecting it to invoke the "[cancel template by version ID](https://coder.com/docs/reference/api/templates#cancel-template-version-by-id)" API. Instead I have an orphaned template version now. For context, this happened to me when I was trying to push a template out with non-existent provisioner tags.