feat(ecs): add neuron to ecs AMI hardware type (#28819)

ECS now supports Amazon ECS optimized Amazon Linux 2 (Neuron) AMI variant for Amazon EC2 Inf1, Trn1 or Inf2 instances (see [here](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-optimized_AMI.html)). It helps make running machine learning inference workloads easier on Amazon ECS.

Add a new enum value, `NEURON` to `AMIHardwareType` to allow users to specify this AMI when setting up their ECS cluster. Add code to retrieve SSM parameter name for this AMI variant (see SSM parameter format for ECS-optimized AMI [here](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/retrieve-ecs-optimized_AMI.html#ecs-optimized-ami-parameter-format)).

Closes #28198 .

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Author: gracelu0