Disk insert/delete doesn't return an LROperation, promise method is missing !

[loganmzz]

Environment details

• OS: Ubuntu 22.04.1 LTS (Jammy Jellyfish)
• Node.js version: v16.14.0
• npm version: none
• yarn version: 1.22.19
• @google-cloud/compute version: 3.5.1

Steps to reproduce

const client = new gcloud.compute.DisksClient();
const [lro] = await client.insert({
  project,
  zone,
  diskResource,
});
return lro.promise; // <-- undefined