Description

This PR addresses multiple E2E test failures at once, by making the following changes:

• regenerate JSON schema
• update test case to account for new default addon (metrics-server)
• ensure some IPv6 related validation are only run on cluster creation (and not on other commands e.g. deletion)
• ensure custom_ami test runs on at least EKS 1.31 as it's the minimum required for the recently added Ubuntu 24.04 support

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the userdocs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes
• (Core team) Added labels for change area (e.g. area/nodegroup) and kind (e.g. kind/improvement)

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟