Fix export

Author: francisco-videira-nhs

lambdas/api-handler/src/index.ts

@@ -1,3 +1,4 @@
 // Export all handlers for ease of access
 export { getLetters } from './handlers/get-letters';
+export { getLetterData } from './handlers/get-letter-data';
 export { patchLetter } from './handlers/patch-letter';