[EKS-AutoMode] [request]: Support for NodeOverlay

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**Tell us about your request**
It could be very helpful to enable NodeOverlays ([link](https://karpenter.sh/docs/concepts/nodeoverlays/)) in EKS-AutoMode, to allow customization of node price/capacity (e.g., to implement proper auto-scaling with fractional GPUs).

**Which service(s) is this request for?**
EKS Auto Mode

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
For example, when using NVIDIA GPU fractioning with MIG "mixed" strategy ([docs](https://docs.nvidia.com/datacenter/cloud-native/kubernetes/latest/index.html#the-mixed-strategy)), cluster auto-scaling does not work, because Karpenter does not recognize the nvidia.com/mig-* resources.

**Are you currently working around this issue?**
NodeOverlays is a new feature in Karpeneter designed to address these (and other) use-cases. However, it is not enabled in EKS Auto Mode.

Start with the NodeOverlays documentation linked in the request and compare it with EKS Auto Mode behavior. Review the NVIDIA mixed MIG strategy documentation to understand the autoscaling failure; done means EKS Auto Mode supports NodeOverlay-based customization and the described fractional-GPU capacity case can scale correctly.

Written by the indexing model from the issue text.