LibWeb/IDB: Implement IDBObjectStore::add

Author: https://github.com/stelar7
Commit: ca1e94f9ea
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4317
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/kennethmyhra ✅

Libraries/LibWeb/IndexedDB/IDBObjectStore.h

@@ -45,6 +45,7 @@ public:
     WebIDL::ExceptionOr<void> delete_index(String const&);
 
     [[nodiscard]] WebIDL::ExceptionOr<GC::Ref<IDBRequest>> add_or_put(GC::Ref<IDBObjectStore>, JS::Value, Optional<JS::Value> const&, bool);
+    [[nodiscard]] WebIDL::ExceptionOr<GC::Ref<IDBRequest>> add(JS::Value value, Optional<JS::Value> const& key);
 
 protected:
     explicit IDBObjectStore(JS::Realm&, GC::Ref<ObjectStore>, GC::Ref<IDBTransaction>);