### 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)
ResourceFormatImporter::get_singleton()->add_importer(import_scene);
		Ref<ResourceImporterScene> import_animation = memnew(ResourceImporterScene(true, true));
		ResourceFormatImporter::get_singleton()->add_importer(import_animation);
		{
			Ref<EditorSceneFormatImporterCollada> import_collada;
			import_collada.instantiate();
			ResourceImporterScene::add_importer(import_collada);
			Ref<EditorOBJImporter> import_obj2;
			import_obj2.instantiate();
			ResourceImporterScene::add_importer(import_obj2);
			Ref<EditorSceneFormatImporterESCN> import_escn;
			import_escn.instantiate();
			ResourceImporterScene::add_importer(import_escn);
		}
		Ref<ResourceImporterBitMap> import_bitmap;
		import_bitmap.instantiate();
		ResourceFormatImporter::get_singleton()->add_importer(import_bitmap);
	}
	{
		Ref<EditorInspectorDefaultPlugin> eidp;
		eidp.instantiate();
		EditorInspector::add_inspector_plugin(eidp);
		Ref<EditorInspectorRootMotionPlugin> rmp;
		rmp.instantiate();
		EditorInspector::add_inspector_plugin(rmp);
		Ref<EditorInspectorVisualShaderModePlugin> smp;
		smp.instantiate();
		EditorInspector::add_inspector_plugin(smp);
	}
	editor_selection = memnew(EditorSelection);