[EKS] [request]: Add support for SSM AMI parameters in Managed Node Groups, Launch Templates

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**Tell us about your request**
When creating a managed node group the resulting Launch Template does not have `ssm:GetParameters`

This is a request for the `ssm:GetParameters` SSM permissions to the `AWSServiceRoleForAmazonEKSNodegroup` role in order to use https://docs.aws.amazon.com/autoscaling/ec2/userguide/using-systems-manager-parameters.html

Without those permissions we can see:
```
"errorCode": "Client.SsmAccessDenied",
"errorMessage": "User: arn:aws:sts::XXXXXXXXXXX:assumed-role/AWSServiceRoleForAmazonEKSNodegroup/EKS is not authorized to perform: ssm:GetParameters on resource: arn:aws:ssm:us-east-1:XXXXXXXXXXX:parameter/ami/eks/XXXXXXXXX because no identity-based policy allows the ssm:GetParameters action"
```
**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?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.
Dynamic AMI ID allocation for self managed addons.

**Are you currently working around this issue?**
How are you currently solving this problem?

Using self-managed nodes seems to be the only workaround here: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ec2-launchtemplate-launchtemplatedata.html#cfn-ec2-launchtemplate-launchtemplatedata-imageid

as the `arn:aws:iam::aws:policy/AmazonSSMManagedInstanceCore` has the `ssm:GetParameters`

Start with the AWS EKS managed node group and Systems Manager Parameter Store documentation linked in the issue, then determine whether the AWSServiceRoleForAmazonEKSNodegroup role can receive ssm:GetParameters for launch-template AMI resolution. Done would mean managed node groups can use SSM AMI parameters without the reported Client.SsmAccessDenied error; the issue names no repository files or tests.

Written by the indexing model from the issue text.