fix: remove default value for `awsRegion` value in cluster-autoscaler Helm...

fix: remove default value for `awsRegion` value in cluster-autoscaler Helm chart to avoid accidental misconfigurations

The region should be specified explicitly. Having a default might be dangerous as cluster-autoscaler might find matching autoscaling groups in other regions that belong to a different cluster and wipe all nodes in them as it doesn't recognize these as belonging to its own cluster.