fix(graphql): required exports for testing

Author: charlypoly

packages/graphql/lib/index.ts

@@ -7,6 +7,7 @@ export * from './graphql-schema.host';
 export * from './graphql-types.loader';
 export * from './graphql.factory';
 export * from './graphql.module';
+export * from './graphql.constants';
 export * from './interfaces';
 export * from './scalars';
 export * from './schema-builder';

packages/graphql/lib/schema-builder/index.ts

@@ -1,3 +1,4 @@
 export * from './storages';
 export * from './graphql-schema.factory';
 export * from './schema-builder.module';
+export * from './helpers/file-system.helper';