### 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)
}
			if (save_accept) {
				save_accept->queue_free();
			}
			editor_data.save_editor_external_data();
			FileAccess::set_file_close_fail_notify_callback(nullptr);
			log->deinit(); 
			editor_data.clear_edited_scenes();
		} break;
		case NOTIFICATION_READY: {
			{
				started_timestamp = Time::get_singleton()->get_unix_time_from_system();
				_initializing_plugins = true;
				Vector<String> addons;
				if (ProjectSettings::get_singleton()->has_setting("editor_plugins/enabled")) {
					addons = GLOBAL_GET("editor_plugins/enabled");
				}
				for (int i = 0; i < addons.size(); i++) {
					set_addon_plugin_enabled(addons[i], true);
				}
				_initializing_plugins = false;
				if (!pending_addons.is_empty()) {
					EditorFileSystem::get_singleton()->connect("script_classes_updated", callable_mp(this, &EditorNode::_enable_pending_addons));
				}
			}
			RenderingServer::get_singleton()->viewport_set_disable_2d(get_scene_root()->get_viewport_rid(), true);
			RenderingServer::get_singleton()->viewport_set_environment_mode(get_viewport()->get_viewport_rid(), RenderingServer::VIEWPORT_ENVIRONMENT_DISABLED);
			feature_profile_manager->notify_changed();
			_select_default_main_screen_plugin();