feat: Apply distinct() on role arns to ensure no duplicated roles in aws-auth configmap

[chrissng]

Description

Apply distinct() on role arns to ensure no duplicated roles in aws auth configmap

Motivation and Context

1. Created a cluster with a couple of eks managed node groups which shared the same iam role names

module "eks" {
  source  = "terraform-aws-modules/eks/aws"
  version = "~> 18.21"

  # other fields...

  eks_managed_node_groups = {
    "dummy_cpu" = {
      "ami_type" = "AL2_x86_64"
      "desired_size" = 1
      "instance_types" = [
        "t3.small",
      ]
      "max_size" = 1
      "min_size" = 0
      # other fields...
    }
    "dummy_gpu" = {
      "ami_type" = "AL2_x86_64_GPU"
      "desired_size" = 0
      "instance_types" = [
        "g4dn.xlarge",
      ]
      "max_size" = 1
      "min_size" = 0
      "taints" = [
        {
          "effect" = "NO_SCHEDULE"
          "key" = "nvidia.com/gpu"
          "value" = "true"
        },
      ]
      # other fields...
    }
    "dummy_testapp_cpu" = {
      "ami_type" = "AL2_x86_64"
      "desired_size" = 1
      "instance_types" = [
        "t3.small",
      ]
      "max_size" = 1
      "min_size" = 0
      # other fields...
    }
    "platform" = {
      "desired_size" = 1
      "instance_types" = [
        "t3.medium",
      ]
      "max_size" = 6
      "min_size" = 0
      # other fields...
    }
  }

  eks_managed_node_group_defaults = {
    "ami_type" = "AL2_x86_64"
    "capacity_type" = "SPOT"
    "create_iam_role" = false
    "iam_role_arn" = "arn:aws:iam::01234567890:role/eks-dummy-worker"
    # other fields...
  }

  manage_aws_auth_configmap = true
  aws_auth_roles            = var.map_roles
  aws_auth_users            = var.map_users
}

2. When the module creates the aws auth configmap, there will be duplicates:

# module.eks.kubernetes_config_map_v1_data.aws_auth[0] will be created
  + resource "kubernetes_config_map_v1_data" "aws_auth" {
      + data  = {
          + "mapAccounts" = jsonencode([])
          + "mapRoles"    = <<-EOT
                - "groups":
                  - "system:bootstrappers"
                  - "system:nodes"
                  "rolearn": "arn:aws:iam::01234567890:role/eks-dummy-worker"
                  "username": "system:node:{{EC2PrivateDNSName}}"
                - "groups":
                  - "system:bootstrappers"
                  - "system:nodes"
                  "rolearn": "arn:aws:iam::01234567890:role/eks-dummy-worker"
                  "username": "system:node:{{EC2PrivateDNSName}}"
                - "groups":
                  - "system:bootstrappers"
                  - "system:nodes"
                  "rolearn": "arn:aws:iam::01234567890:role/eks-dummy-worker"
                  "username": "system:node:{{EC2PrivateDNSName}}"
                - "groups":
                  - "system:bootstrappers"
                  - "system:nodes"
                  "rolearn": "arn:aws:iam::01234567890:role/eks-dummy-worker"
                  "username": "system:node:{{EC2PrivateDNSName}}"
                - "groups":
                  - "dummy"
                  "rolearn": "arn:aws:iam::01234567890:role/dummy"
                ...
            EOT
          + "mapUsers"    = <<-EOT
                - ...
            EOT
        }
      + force = true
      + id    = (known after apply)

      + metadata {
          + name      = "aws-auth"
          + namespace = "kube-system"
        }
    }

3. Although there may not be any effect, but it is probably undesirable to have duplicate role configuration. So this PR addresses this.

Breaking Changes

No breaking changes as it is a minor fix.

How Has This Been Tested?

• I have updated at least one of the examples/* to demonstrate and validate my change(s)
• I have tested and validated these changes using one or more of the provided examples/* projects

• I have executed pre-commit run -a on my pull request

[bryantbiggs]

Makes sense, thanks for the PR @chrissng !

[antonbabenko]

This PR is included in version 18.22.0 🎉

[github-actions]

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