In an application running in AWW EKS, when trying to authenticate to mongo atlas using an AWS IAM Role, the driver should try to get the temporary credentials using the role defined in the environment variable AWS_ROLE_ARN, before getting the temporary credentials using the instance metadata.

This is useful when running an application in AWS EKS, where an AWS IAM Role can be defined for a specific container. In that case the mongo java driver will use this role to get the temporary credentials instead of getting the temporary credentials from the EKS worker node instance metadata.