add new test letter for prod smoke usage (#459)

Author: masl2

scripts/utilities/letter-test-data/src/cli/index.ts

@@ -76,6 +76,7 @@ async function main() {
           choices: [
             "test-letter-large",
             "test-letter-standard",
+            "test-letter-smoke",
             "none", // none exists to specify letter without pdf for error testing scenarios
           ],
         },