test: use IPv6 link-local DNS server

[mkowalski]

This PR changes the test scenario for configuring an incorrect DNS server. Instead of using a fixed 192.x.x.x name server we are now using an IPv6 link-local address fe80::deef:1 parametrized with a NIC name.

The reason for this change is the bug in NetworkManager that prevents rollbacks of incorrect DNS servers applied globally, i.e. not on a specific NIC. As this test explicitly tests the rollback functionality, we want it to explicitly configure a specific NIC and not a global configuration.

By using IPv6 link-local address we are ensure the configuration is applied to the NIC specified, what fulfills the requitement of our test.

Is this a BUG FIX or a FEATURE ?:

/kind bug

What this PR does / why we need it:

Special notes for your reviewer:

Release note:

NONE

[mkowalski]

/test pull-kubernetes-nmstate-unit-test

It may be a valid issue

 /home/prow/go/pkg/mod/github.com/golangci/golangci-lint@v1.55.2/pkg/golinters/musttag.go:4:2: unrecognized import path "go.tmz.dev/musttag": reading https://go.tmz.dev/musttag?go-get=1: 404 Not Found 

[mkowalski]

/retest

[kubevirt-bot]

@mkowalski: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kubernetes-nmstate-e2e-handler-k8s-future	9e7e8ca2d1a4efdefe4d041f0641904523eb19ba	link	false	/test pull-kubernetes-nmstate-e2e-handler-k8s-future

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes/test-infra](https://github.com/kubernetes/test-infra/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[cybertron]

/approve /hold

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cybertron

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/nmstate/kubernetes-nmstate/blob/main/OWNERS)~~ [cybertron] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[mkowalski]

/test pull-kubernetes-nmstate-unit-test

[mkowalski]

/hold cancel