chore(core): bump tag for kubevirt for disable DHCP

[LopatinDmitr]

Description

Bump the 3p-kubevirt component tag from v1.6.2-v12n.25.2 to v1.6.2-v12n.25.3 in build/components/versions.yml.

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

The new kubevirt tag includes the upstream fix that properly disables the DHCP relay in the cluster.
Without this bump, VMs configured to use the disabled DHCP relay path cannot rely on the corrected upstream behavior.

What is the expected result?

1. Apply the change on a target cluster.
2. The 3p-kubevirt image in DVCR is updated to v1.6.2-v12n.25.3.
3. DHCP relay is disabled as expected for affected VMs.

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: core
type: fix
summary: Bump 3p-kubevirt to v1.6.2-v12n.25.3 to disable the DHCP relay.
impact_level: low