Async loading fails because AssetManager's bHasBlueprintClasses does not consider WidgetBlueprint

When bHasBlueprintClasses of AssetManager is enabled, WidgetBlueprint is not included in ClassName of ARFilter.　Therefore, asynchronous loading using AssetManager of the UUserWidget inheritance class that implements GetPrimaryAssetId fails.

Specifically, there is a problem with GetDerivedClasses in the following code in UAssetManager :: ScanPathsForPrimaryAssets.

TArray<UClass*> BlueprintCoreDerivedClasses;
GetDerivedClasses(UBlueprintCore::StaticClass(), BlueprintCoreDerivedClasses);
for (UClass* BPCoreClass : BlueprintCoreDerivedClasses)
{
   ARFilter.ClassNames.Add(BPCoreClass->GetFName());
}
 

If you try to include WidetBlueprint in this ARFilter, it works fine.

1. Open Attached Project
2. Do packaging
3. Run the created exe

expect : print  Loaded
result : print Not Loaded!