Heredoc characters get added in file

Terraform
1

Hello,

I am trying to get list of used ips in an account with this code

resource "null_resource" "used_ips_list" {
  provisioner "local-exec" {
    command = <<-EOT
    aws_credentials=$(aws sts assume-role --role-arn arn:aws:iam::${data.aws_caller_identity.current.account_id}:role/${var.azure_pipeline_iam_role} --role-session-name "RoleSession1" --output json)

    export AWS_ACCESS_KEY_ID=$(echo $aws_credentials|jq '.Credentials.AccessKeyId'|tr -d '"')
    export AWS_SECRET_ACCESS_KEY=$(echo $aws_credentials|jq '.Credentials.SecretAccessKey'|tr -d '"')
    export AWS_SESSION_TOKEN=$(echo $aws_credentials|jq '.Credentials.SessionToken'|tr -d '"')
    aws ec2 describe-network-interfaces --region eu-west-2 --filters "Name=subnet-id,Values=subnet-0ec649f72bb07cdf3" --query 'NetworkInterfaces[*].PrivateIpAddress' > ${data.template_file.subnet_a.rendered}
    EOT
  }
}


data "template_file" "subnet_a" {
  template = "${path.module}/subnet_a"
}


data "local_file" "create-endpoint" {
  filename   = data.template_file.subnet_a.rendered
  depends_on = ["null_resource.used_ips_list"]
}


locals {
  subnet_ip_list = data.local_file.create-endpoint.content
}

However <<EOT- gets added to my file/local variable and looks something like this

"[\n    \"172.18.0.247\",\n    \"172.18.0.253\",\n    \"172.18.0.219\",\n    \"172.18.0.222\",\n    \"172.18.0.254\",\n    \"172.18.0.244\",\n    \"172.18.0.227\",\n    \"172.18.0.224\",\n    \"172.18.0.211\",\n    \"172.18.0.197\",\n    \"172.18.0.246\",\n    \"172.18.0.208\",\n    \"172.18.0.237\",\n    \"172.18.0.238\",\n    \"172.18.0.243\",\n    \"172.18.0.217\",\n    \"172.18.0.248\",\n    \"172.18.0.226\",\n    \"172.18.0.207\"\n]\n"

I tried functions like trim, chomp, split to get a list but best I get is

<<EOT
[
    "172.18.0.247",
    "172.18.0.253",
    "172.18.0.219",
    "172.18.0.222",
    "172.18.0.254",
    "172.18.0.244",
    "172.18.0.227",
    "172.18.0.224",
    "172.18.0.211",
    "172.18.0.197",
    "172.18.0.246",
    "172.18.0.208",
    "172.18.0.237",
    "172.18.0.238",
    "172.18.0.243",
    "172.18.0.217",
    "172.18.0.248",
    "172.18.0.226",
    "172.18.0.207"
]
EOT

How to get a list [“172.18.0.247”,“172.18.0.253”,…] that I can use in other part of code.
I want to use contains function on this list to see if a new IP TF is trying to create is already taken or not,

Thanks !