Terraform does not support email notification for sns subscriptions as this would break the terraform concept. See here:
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/sns_topic_subscription
This module is made for Terraform 12
module "sns_email" {
source = "github.com/noqqe/terraform-modules-aws-sns-email-notification?ref=v0.1.0"
application_name = "my-cloudwatch-alert"
notification_endpoint = "team-alert@example.com"
}