Ensure general purpose SSD node type is not used for AWS ElasticSearch Domains

Using SSDs other than general purpose may lead to surge in costs.

In AWS Console -

1. Sign in to AWS Console and go to the Elasticsearch (ES) dashboard.
2. Click on the ES domain.
3. Open the cluster configuration page.
4. In the storage section verify the EBS Volume type.

In Terraform -

1. In the aws_elasticsearch_domain resource, configure the ebs_options.volume_type appropriately.

References:
https://docs.aws.amazon.com/opensearch-service/latest/developerguide/managedomains-configuration-changes.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/elasticsearch_domain#ebs_options