### 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)
}
	}
	file->set_file_mode(EditorFileDialog::FILE_MODE_SAVE_FILE);
	saving_resource = p_resource;
	current_menu_option = RESOURCE_SAVE_AS;
	List<String> extensions;
	Ref<PackedScene> sd = memnew(PackedScene);
	ResourceSaver::get_recognized_extensions(p_resource, &extensions);
	file->clear_filters();
	List<String> preferred;
	for (const String &E : extensions) {
		if (p_resource->is_class("Script") && (E == "tres" || E == "res")) {
			
			continue;
		}
		file->add_filter("*." + E, E.to_upper());
		preferred.push_back(E);
	}
	
	List<String>::Element *res_element = preferred.find("res");
	if (res_element) {
		preferred.move_to_back(res_element);
	}
	
	List<String>::Element *tres_element = preferred.find("tres");
	if (tres_element) {
		preferred.move_to_front(tres_element);
	}
	if (!p_at_path.is_empty()) {
		file->set_current_dir(p_at_path);