Nodes show the icon of their script type

[mieldepoche]

Godot version

4.1.1

System information

linux

Issue description

Related to #61126

when attaching a script to a node, the displayed icon is stupid (for lack of a better way to put it):
It chooses an icon matching the word after extends regardless of its validity as a type... (it picks it from the editor/icons directory it seems)

In this demo, the node is a Node2D:

simplescreenrecorder-2023-09-03_17.55.26.webm

as you can see extending the script with any class will make the node it's attached to use the class icon, without erroring about incompatibility (unless the word you put isn't actually a valid type).
An error happens only at runtime...

Steps to reproduce

1. attach a script to a node
2. make the script extend any class you'd like, or put a random icon name
3. reload the scene
4. notice the icon usage

Minimal reproduction project

any

[KoBeWi]

Duplicate of #76983
This is fixed in 4.2