[service] [request]: Expose `podLabels` for `snapshot-controller` EKS addon

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**Tell us about your request**
Expose `podLabels` for `snapshot-controller` EKS addon

**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?**
Our entire infrastructure is defined in Terraform, including the EKS addons that we use. We need to add labels to the pods of these addons, and we've been able to do that for all except one - the snapshot-controller

**Are you currently working around this issue?**
Currently we have a separate step to add labels but it's not very reliable and is out side of the "aws_eks_addon" terraform resource.

**Additional context**
No

Start by reviewing the aws_eks_addon Terraform resource and the snapshot-controller EKS addon configuration. Compare how pod labels are exposed for the other addons, then determine what support is needed for snapshot-controller and verify that podLabels can be managed within the resource rather than through a separate step.

Written by the indexing model from the issue text.