chore(core): add comments to prevent accidental adding status subresource

[diafour]

Description

• Add comments to prevent accidental adding status subresource in InternalVirtualizationCDI and InternalVirtualizationVirtualMachineInstance.

Why do we need it, and what problem does it solve?

Some resources for KubeVirt and CDI store status field as "main" fields, not as a subresource. Set status to subresource will break update operation for these resources.

What is the expected result?

Checklist

• [ ] The code is covered by unit tests.
• [ ] e2e tests passed.
• [ ] Documentation updated according to the changes.
• [ ] Changes were tested in the Kubernetes cluster manually.

[diafour]

Status field of VMI should not be a subresource. kubevirt updates status field as a part of "main" payload.