[EKS] [request]: Incorrect Access Policy created for AWS-managed windows node group with custom AMI

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**Tell us about your request**
AWS-managed Windows node group with custom AMI/launch template doesn't get correct permissions when Access Policies are enabled in cluster.

**Which service(s) is this request for?**
EKS

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
We're trying to adopt Access Entries for EKS and we've found that, when creating an AWS-managed Windows node group, the Access Policy is created as "EC2 Linux" rather than "EC2 Windows." The result is that the node doesn't get appropriate cluster permissions and kube-proxy throws errors.

**Are you currently working around this issue?**
We're working around this by creating the Access Policy entry prior to creating the node group.

Start by reviewing the EKS Access Entries and AWS-managed Windows node group behavior described in the issue, including the custom AMI or launch template path. Reproduce the creation flow and verify that the resulting policy is EC2 Windows rather than EC2 Linux, with kube-proxy receiving the required cluster permissions.

Written by the indexing model from the issue text.