### Godot version

4.1.3

### System information

Linux

### Issue description

I'm trying to make an editor plugin on Rust:

```rust
#[derive(GodotClass)]
#[class(tool, editor_plugin, init, base=EditorPlugin)]
pub struct MyEditorPluginBase {}
```

But due to some limitations, I still have to use GDScript for some specific things.

So I tried to make a subclass of this Rust class:

```gdscript
@tool
class_name MyEditorPlugin
extends MyEditorPluginBase
```

This would work if `MyEditorPluginBase` was a GDScript class, but since it's a GDExtension class in my case, it doesn't work:

> Unable to load addon script from path: 'res://addons/my_addon/my_editor_plugin.gd' Base type is not EditorPlugin.

But it obviously **IS** EditorPlugin!

![godot-editorplugin-docs](https://github.com/godotengine/godot/assets/3236464/4665deeb-30f0-45cd-bfff-56101b9d4875)

![godot-editorplugin](https://github.com/godotengine/godot/assets/3236464/b1b6ecb4-de22-4abd-91a3-e180691f67ee)

If I understand correctly, this behavior is caused by this function, which checks some mysterious "instance base type" instead of real inheritance:

https://github.com/godotengine/godot/blob/fa4a65387ea41506ecc519fc61a06da110dce51c/editor/editor_node.cpp#L3456-L3458

https://github.com/godotengine/godot/blob/fa4a65387ea41506ecc519fc61a06da110dce51c/modules/gdscript/gdscript.cpp#L260-L263

Since the [documentation](https://docs.godotengine.org/en/stable/tutorials/plugins/editor/making_plugins.html#the-script-file) doesn't say that the script must be a **direct** subclass of EditorPlugin (and an indirect subclass works fine in GDScript), I interpret this behavior as a Godot bug.

### Steps to reproduce

See above

### Minimal reproduction project

[gdext_editor_plugin_test.zip](https://github.com/godotengine/godot/files/13451014/gdext_editor_plugin_test.zip)
Control *drag_control = memnew(Control);
	TextureRect *drag_preview = memnew(TextureRect);
	Label *label = memnew(Label);
	Ref<Texture2D> preview;
	{
		
		Ref<ImageTexture> texture = theme->get_icon(SNAME("FileBigThumb"), EditorStringName(EditorIcons));
		Ref<Image> img = texture->get_image();
		img = img->duplicate();
		img->resize(48, 48); 
		preview = ImageTexture::create_from_image(img);
	}
	drag_preview->set_texture(preview);
	drag_control->add_child(drag_preview);
	if (p_res->get_path().is_resource_file()) {
		label->set_text(p_res->get_path().get_file());
	} else if (!p_res->get_name().is_empty()) {
		label->set_text(p_res->get_name());
	} else {
		label->set_text(p_res->get_class());
	}
	drag_control->add_child(label);
	p_from->set_drag_preview(drag_control); 
	label->set_position(Point2((preview->get_width() - label->get_minimum_size().width) / 2, preview->get_height()));
	Dictionary drag_data;
	drag_data["type"] = "resource";
	drag_data["resource"] = p_res;
	drag_data["from"] = p_from;