test(test): simplify lsblk size lookup

[danilrwx]

Description

Simplify disk size lookup in the VirtualDiskResizing e2e test.

The test now uses a single lsblk --nodeps --json -o SERIAL,SIZE call and selects the required block device by serial from JSON output, instead of first resolving the device path and then running a second lsblk command for size.

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

VirtualDiskResizing could fail while probing disk sizes because the previous implementation executed multiple SSH commands with lsblk/grep/awk. Under hotplug/resize activity this made the check more fragile and increased the chance of timeout-related signal: killed errors.

Using one simple JSON-based lsblk call reduces the amount of SSH work and avoids shell parsing for device path lookup.

What is the expected result?

1. Run VirtualDiskResizing e2e test.
2. Verify disk size checks find the expected devices by serial.
3. Verify test/e2e lint reports no issues.

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.

Changelog entries

section: test
type: fix
summary: Simplify VirtualDiskResizing disk size checks to reduce SSH command flakiness.
impact_level: low