APIServerLB DNS name resolution causes deploy failure on air-gapped systems

[r4f4]

/kind bug

What steps did you take and what happened:
After CAPA creates the APIServer Load Balancer and it gets a DNS name, CAPA waits for the DNS name to resolve before continuing the installation [1][2]. I think this check was never reconsidered when support for a secondary LB was added.

Now consider the scenario where a cluster is deployed on an air-gapped system. Trying to resolve the LB DNS name will never succeed .

[1] #1641
[2] #1651

What did you expect to happen:
Only check for DNS name resolution when the APIServer LB is public.

Anything else you would like to add:
Air-gapped installations are a requirement in C2S/SC2S secret regions.

Environment:

• Cluster-api-provider-aws version: master
• Kubernetes version: (use kubectl version): 1.29
• OS (e.g. from /etc/os-release):

[k8s-ci-robot]

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