GraphQL: Optimize queries, fixes some null returns (on object), fix stitched GraphQLUpload (#6709)

* Optimize query, fixes some null returns, fix stitched GraphQLUpload

* Fix authData key selection

* Prefer Iso string since other GraphQL solutions use this format

* fix tests

Co-authored-by: Antonio Davi Macedo Coelho de Castro <adavimacedo@gmail.com>

src/Routers/FunctionsRouter.js

@@ -4,7 +4,10 @@ var Parse = require('parse/node').Parse,
   triggers = require('../triggers');
 
 import PromiseRouter from '../PromiseRouter';
-import { promiseEnforceMasterKeyAccess, promiseEnsureIdempotency } from '../middlewares';
+import {
+  promiseEnforceMasterKeyAccess,
+  promiseEnsureIdempotency,
+} from '../middlewares';
 import { jobStatusHandler } from '../StatusHandler';
 import _ from 'lodash';
 import { logger } from '../logger';