### 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)
OS::get_singleton()->set_display_driver_id(display_driver_idx);
	GLOBAL_DEF_RST_NOVAL("audio/driver/driver", AudioDriverManager::get_driver(0)->get_name());
	if (audio_driver.is_empty()) { 
		audio_driver = GLOBAL_GET("audio/driver/driver");
	}
	
	DEV_ASSERT(NULL_AUDIO_DRIVER == AudioDriverManager::get_driver(AudioDriverManager::get_driver_count() - 1)->get_name());
	for (int i = 0; i < AudioDriverManager::get_driver_count(); i++) {
		if (audio_driver == AudioDriverManager::get_driver(i)->get_name()) {
			audio_driver_idx = i;
			break;
		}
	}
	if (audio_driver_idx < 0) {
		
		
		audio_driver_idx = 0;
	}
	if (Engine::get_singleton()->get_write_movie_path() != String()) {
		
		audio_driver_idx = AudioDriverManager::get_driver_count() - 1;
		AudioDriverDummy::get_dummy_singleton()->set_use_threads(false);
	}
	{
		window_orientation = DisplayServer::ScreenOrientation(int(GLOBAL_DEF_BASIC("display/window/handheld/orientation", DisplayServer::ScreenOrientation::SCREEN_LANDSCAPE)));
	}
	{
		window_vsync_mode = DisplayServer::VSyncMode(int(GLOBAL_DEF_BASIC("display/window/vsync/vsync_mode", DisplayServer::VSyncMode::VSYNC_ENABLED)));