[FIX] [JETSTREAM] [OS] The field error in ObjectResult was someti…

…mes set to `undefined`, when needed to be `null` if no error.

jetstream/objectstore.ts

@@ -567,7 +567,7 @@ export class ObjectStoreImpl implements ObjectStore {
       }
     })()
       .then(() => {
-        d.resolve();
+        d.resolve(null);
       })
       .catch((err) => {
         controller!.error(err);