Use enabled instead of count

enabled.tf

data "aws_iam_policy_document" "data" {
  enabled = terraform.workspace == "production"

  statement {
    actions = [
      "s3:GetBucketLocation",
      "s3:ListBucket",
    ]

    resources = [
      aws_s3_bucket.data.arn,
    ]
  }

  statement {
    actions = [
      "s3:GetObject",
      "s3:PutObject",
    ]

    resources = [
      "${aws_s3_bucket.data.arn}/*",
      aws_s3_bucket.data.arn,
    ]
  }
}