### 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)
left_menu_spacer = memnew(Control);
		left_menu_spacer->set_mouse_filter(Control::MOUSE_FILTER_PASS);
		title_bar->add_child(left_menu_spacer);
	}
	main_menu = memnew(MenuBar);
	title_bar->add_child(main_menu);
	main_menu->add_theme_style_override("hover", theme->get_stylebox(SNAME("MenuHover"), EditorStringName(EditorStyles)));
	main_menu->set_flat(true);
	main_menu->set_start_index(0); 
	main_menu->set_prefer_global_menu(global_menu);
	main_menu->set_switch_on_hover(true);
	file_menu = memnew(PopupMenu);
	file_menu->set_name(TTR("Scene"));
	main_menu->add_child(file_menu);
	main_menu->set_menu_tooltip(0, TTR("Operations with scene files."));
	accept = memnew(AcceptDialog);
	accept->set_unparent_when_invisible(true);
	save_accept = memnew(AcceptDialog);
	save_accept->set_unparent_when_invisible(true);
	save_accept->connect("confirmed", callable_mp(this, &EditorNode::_menu_option).bind((int)MenuOptions::FILE_SAVE_AS_SCENE));
	project_export = memnew(ProjectExportDialog);
	gui_base->add_child(project_export);
	dependency_error = memnew(DependencyErrorDialog);
	gui_base->add_child(dependency_error);
	dependency_fixer = memnew(DependencyEditor);
	gui_base->add_child(dependency_fixer);
	editor_settings_dialog = memnew(EditorSettingsDialog);
	gui_base->add_child(editor_settings_dialog);
	project_settings_editor = memnew(ProjectSettingsEditor(&editor_data));
	gui_base->add_child(project_settings_editor);