Thumbnail is not displayed in the Editor for UPaperSprite properties

A UPaperSprite* property in a class does not show a thumbnail for the property in the Editor. This is different from other asset poperties, such as UTexture* or UStaticMesh*, which do show a thumbnail in the Editor.

The UPaperSprite class does contain meta=(DisplayThumbnail = "true") in its UCLASS, but this metadata does not seem to be getting checked when the Editor is deciding whether or not to display a thumbnail. The metadata in the property's UPROPERTY is checked, but adding the metadata there is an extra step that is not needed for other asset classes.

Regression
No

1. Create a new Code project.
2. Open the project in the Editor.
3. Add a new Actor code class.
4. In Visual Studio, open your project's Build.cs file and add "Paper2D" to the PublicDependencyModuleNames.
5. In the header file for the new Actor class, add the following property:

   UPROPERTY(EditDefaultsOnly)
   class UPaperSprite* SpritePtr;
   

6. Build the project in Visual Studio.
7. Create a new Blueprint derived from the new Actor class.
8. Open the Blueprint.

RESULT:
The UPaperSprite property does not show a thumbnail.

EXPECTED:
The UPaperSprite property shows a thumbnail.

WORKAROUND:
Add meta=(DisplayThumbnail = "true") to the UPROPERTY for the UPaperSprite property.