fix(vi): validate `VirtualImage` storage class

[hardcoretime]

Description

A temporary solution until the problem with PersistentVolumeMode is resolved.

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

This is currently required to prevent a VirtualImage from being created with the PersistentVolumeFilesystem storage class.

What is the expected result?

VirtualImage cannot be created the PersistentVolumeFilesystem storage class.

Checklist

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

Changelog entries

section: vi 
type: fix
summary:  "Prevent a `VirtualImage` from being created with the `PersistentVolumeFilesystem` storage class."
impact_level: high
impact: |
  `VirtualImage` cannot be created the `PersistentVolumeFilesystem` storage class.