remove downlevel iterator setting

Author: sawka

tsconfig.json

@@ -13,7 +13,6 @@
         "resolveJsonModule": true,
         "isolatedModules": true,
         "experimentalDecorators": true,
-        "downlevelIteration": true,
         "baseUrl": "./",
         "paths": {
             "@/app/*": ["frontend/app/*"],