Teleskope needs read access to scan and classify your data stored in SNS.
Attach the AmazonSNSReadOnlyAccess to the Teleskope IAM role you created.
resource "aws_iam_role_policy_attachment" "sns_policy" {
role = "TeleskopeRole"
policy_arn = "arn:aws:iam::aws:policy/AmazonSNSReadOnlyAccess"
}