[EKS] [addon]: Support Flux V2 in EKS addons

### Community Note

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**Tell us about your request**
Please add Flux V2 in EKS addons. There is a helm chart now so should be relatively easy. See https://github.com/fluxcd-community/helm-charts

**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?**
Need to get flux installed reliably and simply in the EKS cluster in a way that is easy to upgrade without breaking all the installed resources by flux.
**Are you currently working around this issue?**
Flux and kubernetes provider in terraform but this is unreliable and can fail silently.
Flux have a command line flux bootstrap but this needs organisational access to the github repo and is unnecessary once a git repo has been setup.

**Additional context**
Once flux is installed then flux can automatically install the rest of the kubernets resources so its a big win in eks can do this in the addons.

**Attachments**
See https://github.com/fluxcd-community/helm-charts for the charts

Start by reviewing the repository's existing EKS addon support and the Flux Community Helm charts linked in the issue. Define done as Flux V2 being installable and upgradeable through EKS addons without breaking resources; the issue names no files, tests, or implementation entry point.

Written by the indexing model from the issue text.