aws-ec2: Add Graviton 5 (`InstanceClass.M9G`) to available instance classes

[garysassano]

Describe the feature

M9g instances aren't available in CDK.

Use Case

See above.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

AWS CDK Library version (aws-cdk-lib)

2.232.1

AWS CDK CLI version

2.1033.0

Environment details (OS name and version, etc.)

Ubuntu 24.04

[pahud]

Hi

Looks like M9g is current in preview but we can follow the established pattern of M8g from #32528 to add the enum support.

We welcome the PR.