### 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)
execute_output_dialog = memnew(AcceptDialog);
	execute_output_dialog->set_unparent_when_invisible(true);
	execute_output_dialog->add_child(execute_outputs);
	execute_output_dialog->set_title("");
	EditorFileSystem::get_singleton()->connect("sources_changed", callable_mp(this, &EditorNode::_sources_changed));
	EditorFileSystem::get_singleton()->connect("filesystem_changed", callable_mp(this, &EditorNode::_fs_changed));
	EditorFileSystem::get_singleton()->connect("resources_reimported", callable_mp(this, &EditorNode::_resources_reimported));
	EditorFileSystem::get_singleton()->connect("resources_reload", callable_mp(this, &EditorNode::_resources_changed));
	_build_icon_type_cache();
	pick_main_scene = memnew(ConfirmationDialog);
	gui_base->add_child(pick_main_scene);
	pick_main_scene->set_ok_button_text(TTR("Select"));
	pick_main_scene->connect("confirmed", callable_mp(this, &EditorNode::_menu_option).bind(SETTINGS_PICK_MAIN_SCENE));
	select_current_scene_button = pick_main_scene->add_button(TTR("Select Current"), true, "select_current");
	pick_main_scene->connect("custom_action", callable_mp(this, &EditorNode::_pick_main_scene_custom_action));
	for (int i = 0; i < _init_callbacks.size(); i++) {
		_init_callbacks[i]();
	}
	editor_data.add_edited_scene(-1);
	editor_data.set_edited_scene(0);
	scene_tabs->update_scene_tabs();
	ImportDock::get_singleton()->initialize_import_options();
	FileAccess::set_file_close_fail_notify_callback(_file_access_close_error_notify);
	print_handler.printfunc = _print_handler;
	print_handler.userdata = this;
	add_print_handler(&print_handler);
	ResourceSaver::set_save_callback(_resource_saved);
	ResourceLoader::set_load_callback(_resource_loaded);
	
	ED_SHORTCUT_AND_COMMAND("editor/editor_2d", TTR("Open 2D Editor"), KeyModifierMask::CTRL | Key::F1);