tests: add descheduler e2e tests

[yaroslavborbat]

Description

add descheduler e2e tests

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

What is the expected result?

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: core
type: feature
summary: add descheduler e2e tests
impact_level: low