create AWSManagedControlPlane fails in a private vpc due to IAM API requirement

[AhyeongLee]

/kind bug

What steps did you take and what happened:
[A clear and concise description of what the bug is.]

I applied below AWSManagedControlPlane

apiVersion: controlplane.cluster.x-k8s.io/v1beta2
kind: AWSManagedControlPlane
metadata:
  name: my-cluster-control-plane
  namespace: cluster-api
spec:
  region: ap-northeast-2
  version: v1.27.0
  network:
    vpc:
      id: vpc-id
    subnets:
    - id: subnet-id1
    - id: subnet-id2
  bastion:
    enabled: false
  roleName: TEST-ROLE

And I got error message

E0326 07:44:29.203901       1 controller.go:329] "Reconciler error" err=<
        failed to reconcile control plane for AWSManagedControlPlane cluster-api/aylee-cluster-control-plane: RequestError: send request failed
        caused by: Post "https://iam.amazonaws.com/": dial tcp 44.216.198.236:443: i/o timeout

My VPC is private and there's no VPC Endpoint available for IAM api
I am curious about how to create an AWSManagedControlPlane in a private vpc.

What did you expect to happen:

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• Cluster-api-provider-aws version: cluster-api-aws-controller:v2.4.1
• Kubernetes version: (use kubectl version): 1.27
• OS (e.g. from /etc/os-release):

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