Placeable UCLASS specifier doesn't override parent classes NotPlaceable UCLASS specifier

When the child of an actor with the UCLASS specifier NotPlaceable has the UCLASS specifier Placeable it still isn't placeable. This behavior doesn't occur in 4.20.3.

Found in 4.22 CL#7053642
Reproduced in 4.24 CL#7273411, 4.21 CL#4753647

1. Create a clean project.
2. Create a new C++ ParentActor class based on AActor and use the 'NotPlaceable' specifier in UCLASS.
3. Create a new C++ ChildActor class based on ParentActor and use the 'Placeable' specifier in UCLASS.
4. Compile and try to place a ChildActor into a level.

Result: An instance of ChildActor cannot be placed in a level.

Expected: An instance of ChildActor can be placed in a level.