### 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)
}
		} else if (current_res->get_path().is_resource_file()) {
			if (FileAccess::exists(current_res->get_path() + ".import")) {
				editable_info = TTR("This resource was imported, so it's not editable. Change its settings in the import panel and then re-import.");
			}
		}
	} else if (is_node) {
		Node *current_node = Object::cast_to<Node>(current_obj);
		ERR_FAIL_NULL(current_node);
		InspectorDock::get_inspector_singleton()->edit(current_node);
		if (current_node->is_inside_tree()) {
			NodeDock::get_singleton()->set_node(current_node);
			SceneTreeDock::get_singleton()->set_selected(current_node);
			InspectorDock::get_singleton()->update(current_node);
			if (!inspector_only && !skip_main_plugin) {
				skip_main_plugin = stay_in_script_editor_on_node_selected && !ScriptEditor::get_singleton()->is_editor_floating() && ScriptEditor::get_singleton()->is_visible_in_tree();
			}
		} else {
			NodeDock::get_singleton()->set_node(nullptr);
			SceneTreeDock::get_singleton()->set_selected(nullptr);
			InspectorDock::get_singleton()->update(nullptr);
		}
		if (get_edited_scene() && !get_edited_scene()->get_scene_file_path().is_empty()) {
			String source_scene = get_edited_scene()->get_scene_file_path();
			if (FileAccess::exists(source_scene + ".import")) {
				editable_info = TTR("This scene was imported, so changes to it won't be kept.\nInstantiating or inheriting it will allow you to make changes to it.\nPlease read the documentation relevant to importing scenes to better understand this workflow.");
				info_is_warning = true;
			}
		}
	} else {