### 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)
EditorExport::get_singleton()->add_export_plugin(gdextension_export_plugin);
	Ref<DedicatedServerExportPlugin> dedicated_server_export_plugin;
	dedicated_server_export_plugin.instantiate();
	EditorExport::get_singleton()->add_export_plugin(dedicated_server_export_plugin);
	Ref<PackedSceneEditorTranslationParserPlugin> packed_scene_translation_parser_plugin;
	packed_scene_translation_parser_plugin.instantiate();
	EditorTranslationParser::get_singleton()->add_parser(packed_scene_translation_parser_plugin, EditorTranslationParser::STANDARD);
	_edit_current();
	current = nullptr;
	saving_resource = Ref<Resource>();
	set_process(true);
	open_imported = memnew(ConfirmationDialog);
	open_imported->set_ok_button_text(TTR("Open Anyway"));
	new_inherited_button = open_imported->add_button(TTR("New Inherited"), !DisplayServer::get_singleton()->get_swap_cancel_ok(), "inherit");
	open_imported->connect("confirmed", callable_mp(this, &EditorNode::_open_imported));
	open_imported->connect("custom_action", callable_mp(this, &EditorNode::_inherit_imported));
	gui_base->add_child(open_imported);
	quick_open = memnew(EditorQuickOpen);
	gui_base->add_child(quick_open);
	quick_open->connect("quick_open", callable_mp(this, &EditorNode::_quick_opened));
	_update_recent_scenes();
	set_process_shortcut_input(true);
	load_errors = memnew(RichTextLabel);
	load_error_dialog = memnew(AcceptDialog);
	load_error_dialog->set_unparent_when_invisible(true);
	load_error_dialog->add_child(load_errors);
	load_error_dialog->set_title(TTR("Load Errors"));
	execute_outputs = memnew(RichTextLabel);
	execute_outputs->set_selection_enabled(true);
	execute_outputs->set_context_menu_enabled(true);