[Bug] CapacityReservationId doesn't work

[Shellmode]

What were you trying to accomplish?

Use eksctl to create a nodegroup with capacity block reservation.

BTW, great to have this feature at #8207

What happened?

The cloudformation template created by eksctl doesn't contain CapacityReservationId field.

How to reproduce it?

Use following commands to reproduce (But I think it might be difficult to have a real CapacityReservationId for dev team to debug)

## Change to your own
VPCID="vpc-123456789012"
SUBNET="subnet-123456789012"
CLUSTER_NAME="test-cluster"
AWS_DEFAULT_REGION="ap-southeast-3" # not sure if it's region related, so keep to my problem region
K8S_VERSION="1.32"

cat << EOF > al2-gpu-p5en.48xlarge-nodegroup.yaml
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: ${CLUSTER_NAME}
  region: ${AWS_DEFAULT_REGION}

managedNodeGroups:
- name: p5en-ng-efa-al2
  instanceType: p5en.48xlarge
  amiFamily: AmazonLinux2
  privateNetworking: true
  efaEnabled: true
  capacityReservation:
    capacityReservationTarget:
      capacityReservationId: "cr-1234567890"  # Replace with a real Capacity Block ID
  instanceMarketOptions:
    marketType: capacity-block
  iam:
    attachPolicyARNs:
    - arn:aws:iam::aws:policy/AmazonEKSWorkerNodePolicy
    - arn:aws:iam::aws:policy/AmazonEKS_CNI_Policy
    - arn:aws:iam::aws:policy/AmazonEC2ContainerRegistryReadOnly
    - arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore
    - arn:aws:iam::aws:policy/CloudWatchAgentServerPolicy        
  desiredCapacity: 1
  minSize: 1
  maxSize: 1
  volumeSize: 200
  tags:
    "eks/node-type": "gpu"
  labels:
    eks/node-type: gpu
    eks/gpu-type: nvidia
    nvidia.com/gpu.present: "true"
  taints:
  - key: nvidia.com/gpu
    effect: "NoSchedule"
  subnets:
      - ${SUBNET} 
  ssh: # use existing EC2 key
    publicKeyName: testkey
      
EOF

The cloudformation template created by eksctl is just like this, missing CapacityReservationId field, which makes the stack failed

{
...
           "LaunchTemplate": {
            "Type": "AWS::EC2::LaunchTemplate",
            "Properties": {
                "LaunchTemplateData": {
                    ...
                    "CapacityReservationSpecification": {
                        "CapacityReservationTarget": {}
                    },
                    ...
...
}

I have to download the template, edit it and create a new one.

Logs

Anything else we need to know?

Versions

$ eksctl info
eksctl version: 0.206.0
kubectl version: v1.32.0-eks-5ca49cb
OS: linux

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