Unable to see class_name on exported Dictionary values

[Rubonnek]

Godot version:
3.2 branch commit 23b553b

OS/device including version:
Arch Linux

Issue description:
On an exported dictionary, setting a key or value to Object and then choosing the class_name object does not show the original class_name on Inspector but Godot's built-in base class instead.

Steps to reproduce:
On the attached project:

1. Click on the only node in the scene tree.
2. Look at the script variables section of the Inspector
3. What says Resource should say AwesomeClass:
   

Minimal reproduction project:
ClassNameTest.zip

[Rubonnek]

Duplicate of #21789

[Rubonnek]

Actually, it's possible to see this in the editor. One needs to set the resource name within the script's _init method like so:

tool
...
func _init():
    resource_name = "AwesomeClass"

Just found out about this and seems to be undocumented.