[EKS] [request]: Add support for securityContext in kube-proxy add-on configuration

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**Tell us about your request**
Provide support for `kube-proxy` add-on to specify security context in configuration. Specifically looking to be able to drop capabilities like this (and add only necessary ones):
```
securityContext:
capabilities:
drop:
- ALL
```
At the moment, the latest version `v1.26.11-eksbuild.4` doesn't support it.

**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?**
Cyber Cecurity team want to reduce attack surface and improve EKS cluster security posture.

**Are you currently working around this issue?**
Nope, as add-on config is managed by AWS.

**Additional context**
None

**Attachments**
None.

Start by reviewing how the EKS kube-proxy add-on configuration is exposed; the issue names no repository files or tests. Done means the configuration accepts a securityContext, including capabilities such as dropping ALL, for the kube-proxy add-on.

Written by the indexing model from the issue text.