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>

spec/defaultGraphQLTypes.spec.js

@@ -473,7 +473,7 @@ describe('defaultGraphQLTypes', () => {
 
       it('should serialize date', () => {
         const date = new Date();
-        expect(serialize(date)).toBe(date.toUTCString());
+        expect(serialize(date)).toBe(date.toISOString());
       });
 
       it('should return iso value if object', () => {