aws-eks: Support AL2_ARM_64_GPU NodeGroupAmiType

### Describe the feature

Using the aws-eks library it would be great if I was able to create a nodeGroup with a Graviton GPU instance like the g5g class. However, the NodegroupAmiType does not support AL2_ARM_64_GPU only AL2_ARM_64 which gets denied when trying to synth cdk. If I don't specify the amiType it defaults to AL2_x86_64_GPU and errors out that the g5g.xlarge is not a valid instance type for the requested amiType.

### Use Case

To create a nodeGroup with a g5g instance type

### Proposed Solution

add support for AL2_ARM_64_GPU to the NodegroupAmiType enum.

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.87.0

### Environment details (OS name and version, etc.)

Mac os 12.4

Start in the aws-eks library at the NodegroupAmiType enum and inspect how the amiType is validated during CDK synth. Verify the g5g instance type with AL2_ARM_64_GPU, then confirm synthesis accepts the new combination without the existing AMI type error.

Written by the indexing model from the issue text.