### 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 (!saver[i]->recognize_path(p_resource, path)) {
			continue;
		}
		String old_path = p_resource->get_path();
		String local_path = ProjectSettings::get_singleton()->localize_path(path);
		Ref<Resource> rwcopy = p_resource;
		if (p_flags & FLAG_CHANGE_PATH) {
			rwcopy->set_path(local_path);
		}
		err = saver[i]->save(p_resource, path, p_flags);
		if (err == OK) {
#ifdef TOOLS_ENABLED
			((Resource *)p_resource.ptr())->set_edited(false);
			if (timestamp_on_save) {
				uint64_t mt = FileAccess::get_modified_time(path);
				((Resource *)p_resource.ptr())->set_last_modified_time(mt);
			}
#endif
			if (p_flags & FLAG_CHANGE_PATH) {
				rwcopy->set_path(old_path);
			}
			if (save_callback && path.begins_with("res://")) {
				save_callback(p_resource, path);
			}
			return OK;
		}
	}
	return err;
}
Error ResourceSaver::set_uid(const String &p_path, ResourceUID::ID p_uid) {