test(api): add e2e sizing policy test

[hardcoretime]

Description

The tests of the e2e sizing policy cover the following cases:

• creating virtual machine with non-existing vmClass;
• creating virtual machine with existing vmClass;
• validate virtual machine spec with sizing policy.

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

What is the expected result?

Checklist

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