Karpenter module not compatible with AWS China

[fitillo]

Description

Policy created for karpenter controller doesn't work for AWS China. The problem is inside controller's policy: https://github.com/terraform-aws-modules/terraform-aws-eks/blob/v21.15.1/modules/karpenter/policy.tf#L237

Code contemplates adding ec2.amazonaws.com.cn when executing in China. The problem is that aws_service_principal is not working as expected. There's an open issue for it here: hashicorp/terraform-provider-aws#46209 that I'm able to reproduce.

I propose reverting to previous code in v20. I've already tested it in my local setup and it works.

1. Add local dns_suffix = data.aws_partition.current[0].dns_suffix in main.tf
2. Modify line 237 in policy.tf to: values = distinct(["ec2.${local.dns_suffix}", "ec2.amazonaws.com"])

I'd be happy to add the PR for this one.

[fitillo]

Added PR: #3651

[bryantbiggs]

it is correct as written, the upstream provider needs to be corrected