chore(ec2): add r8gn instance classes

[phuhung273]

Reason for this change

https://aws.amazon.com/about-aws/whats-new/2025/09/generally-available-amazon-ec2-r8gn-instances/

Description of changes

Add r8gn instance classes

Description of how you validated changes

$ aws ec2 describe-instance-types | grep -e r8gn
            "InstanceType": "r8gn.12xlarge",
            "InstanceType": "r8gn.2xlarge",
...

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[alvazjor]

Thanks for the contribution

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[mergify]

This pull request has been removed from the queue for the following reason: checks failed.

The merge conditions cannot be satisfied due to failing checks:

You may have to fix your CI before adding the pull request to the queue again.
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[alvazjor]

@Mergifyio requeue

[mergify]

requeue

✅ The queue state of this pull request has been cleaned. It can be re-embarked automatically

[phuhung273]

Thanks for your review @alvazjor. Seems like PR Linter stuck due to token issue 😄

[alvazjor]

Yep, team is aware and looking into it

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

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