[EKS] [Feature Request]: Observe control plane size and resizing events in the EKS observability dashboards

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**Tell us about your request**
Include control plane size and resizing event widgets in the EKS Observability dashboards, specifically on the Control Plane monitoring tab.

**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?**
Currently, EKS customers don't have any insight into their current EKS control plane bundle size or when a resizing event occurs. Being able to observe their control plane size over time would help the customer more accurately choose which scaling tier is best for them. Resizing events can impact downstream services. For example, when the control plane scales up, additional load is put on the metrics-server to handle increased HPA API requests. Also, we've noticed that resizing events can lead to restarts of the Secrets Store CSI Driver pods.

**Are you currently working around this issue?**
We don't have any definitive information that a resizing event occurred and therefore have to infer one happened by piecing together data from various sources, e.g. 2x CPU load on metrics server, 2x control plane API requests, restarts of mission-critical tools that rely heavily on the control plane, etc. We've also opened AWS cases in the past to confirm our diagnosis of a control plane resizing event.

**Additional context**
Providing this information would significantly reduce the MTTD why downstream services are acting abnormally and allow your customers to more accurately choose which scaling tier will work best for them.

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