### 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)
editor_layout_save_delay_timer->start();
}
void EditorNode::_dock_split_dragged(int ofs) {
	editor_layout_save_delay_timer->start();
}
void EditorNode::_load_editor_layout() {
	Ref<ConfigFile> config;
	config.instantiate();
	Error err = config->load(EditorPaths::get_singleton()->get_project_settings_dir().path_join("editor_layout.cfg"));
	if (err != OK) { 
		
		TreeItem *root = FileSystemDock::get_singleton()->get_tree_control()->get_item_with_metadata("res:", 0);
		if (root) {
			root->set_collapsed(false);
		}
		TreeItem *favorites = FileSystemDock::get_singleton()->get_tree_control()->get_item_with_metadata("Favorites", 0);
		if (favorites) {
			favorites->set_collapsed(false);
		}
		if (overridden_default_layout >= 0) {
			_layout_menu_option(overridden_default_layout);
		}
		return;
	}
	_load_docks_from_config(config, "docks");
	_load_open_scenes_from_config(config);
	_load_central_editor_layout_from_config(config);
	editor_data.set_plugin_window_layout(config);
}
void EditorNode::_update_dock_slots_visibility(bool p_keep_selected_tabs) {