### 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)
opening_prev = false;
		if (prev != -1) {
			_set_current_scene(prev);
			editor_data.remove_scene(idx);
		}
		return ERR_FILE_CORRUPT;
	}
	if (p_set_inherited) {
		Ref<SceneState> state = sdata->get_state();
		state->set_path(lpath);
		new_scene->set_scene_inherited_state(state);
		new_scene->set_scene_file_path(String());
	}
	new_scene->set_scene_instance_state(Ref<SceneState>());
	set_edited_scene(new_scene);
	String config_file_path = EditorPaths::get_singleton()->get_project_settings_dir().path_join(p_scene.get_file() + "-editstate-" + p_scene.md5_text() + ".cfg");
	Ref<ConfigFile> editor_state_cf;
	editor_state_cf.instantiate();
	Error editor_state_cf_err = editor_state_cf->load(config_file_path);
	if (editor_state_cf_err == OK || editor_state_cf->has_section("editor_states")) {
		_load_editor_plugin_states_from_config(editor_state_cf);
	}
	_update_title();
	scene_tabs->update_scene_tabs();
	_add_to_recent_scenes(lpath);
	if (editor_folding.has_folding_data(lpath)) {
		editor_folding.load_scene_folding(new_scene, lpath);
	} else if (EDITOR_GET("interface/inspector/auto_unfold_foreign_scenes")) {
		editor_folding.unfold_scene(new_scene);
		editor_folding.save_scene_folding(new_scene, lpath);