Avoid creating metallb config if unnecessary

[oomichi]

What type of PR is this?

/kind bug

What this PR does / why we need it:

To avoid the following error during setting metallb up, this adds some conditions:

 TASK [kubernetes_sigs.kubespray.kubernetes-apps/metallb : Kubernetes Apps | Lay Down MetalLB] ***
 [..]
  An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible.errors.AnsibleUndefinedVariable: 'dict object' has no attribute 'controller'
  failed: [k8s-master-1] (item=metallb.yml) => {"ansible_loop_var": "item", "changed": false, "item": "metallb.yml", "msg": "AnsibleUndefinedVariable: 'dict object' has no attribute 'controller'"}
  An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible.errors.AnsibleUndefinedVariable: 'dict object' has no attribute 'layer3'
  failed: [k8s-master-1] (item=layer3.yaml) => {"ansible_loop_var": "item", "changed": false, "item": "layer3.yaml", "msg": "AnsibleUndefinedVariable: 'dict object' has no attribute 'layer3'"}

Which issue(s) this PR fixes:

Fixes #10143

Does this PR introduce a user-facing change?:

Avoid creating metallb config if unnecessary

[k8s-ci-robot]

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[Jeroen0494]

Will be fixed in #9995

[k8s-ci-robot]

PR needs rebase.

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[oomichi]

Will be fixed in #9995

Thanks for pointing it out.
OK, let's close this pr.