### 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)
file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/new_inherited_scene", TTR("New Inherited Scene..."), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + Key::N), FILE_NEW_INHERITED_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/open_scene", TTR("Open Scene..."), KeyModifierMask::CMD_OR_CTRL + Key::O), FILE_OPEN_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/reopen_closed_scene", TTR("Reopen Closed Scene"), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + Key::T), FILE_OPEN_PREV);
	file_menu->add_submenu_item(TTR("Open Recent"), "RecentScenes", FILE_OPEN_RECENT);
	file_menu->add_separator();
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/save_scene", TTR("Save Scene"), KeyModifierMask::CMD_OR_CTRL + Key::S), FILE_SAVE_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/save_scene_as", TTR("Save Scene As..."), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + Key::S), FILE_SAVE_AS_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/save_all_scenes", TTR("Save All Scenes"), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + KeyModifierMask::ALT + Key::S), FILE_SAVE_ALL_SCENES);
	file_menu->add_separator();
	file_menu->add_shortcut(ED_SHORTCUT_ARRAY_AND_COMMAND("editor/quick_open", TTR("Quick Open..."), { int32_t(KeyModifierMask::SHIFT + KeyModifierMask::ALT + Key::O), int32_t(KeyModifierMask::CMD_OR_CTRL + Key::P) }), FILE_QUICK_OPEN);
	ED_SHORTCUT_OVERRIDE_ARRAY("editor/quick_open", "macos", { int32_t(KeyModifierMask::META + KeyModifierMask::CTRL + Key::O), int32_t(KeyModifierMask::CMD_OR_CTRL + Key::P) });
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/quick_open_scene", TTR("Quick Open Scene..."), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + Key::O), FILE_QUICK_OPEN_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/quick_open_script", TTR("Quick Open Script..."), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::ALT + Key::O), FILE_QUICK_OPEN_SCRIPT);
	file_menu->add_separator();
	export_as_menu = memnew(PopupMenu);
	export_as_menu->set_name("Export");
	file_menu->add_child(export_as_menu);
	file_menu->add_submenu_item(TTR("Export As..."), "Export");
	export_as_menu->add_shortcut(ED_SHORTCUT("editor/export_as_mesh_library", TTR("MeshLibrary...")), FILE_EXPORT_MESH_LIBRARY);
	export_as_menu->connect("index_pressed", callable_mp(this, &EditorNode::_export_as_menu_option));
	file_menu->add_separator();
	file_menu->add_shortcut(ED_GET_SHORTCUT("ui_undo"), EDIT_UNDO, true, true);
	file_menu->add_shortcut(ED_GET_SHORTCUT("ui_redo"), EDIT_REDO, true, true);
	file_menu->add_separator();
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/reload_saved_scene", TTR("Reload Saved Scene")), EDIT_RELOAD_SAVED_SCENE);
	file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/close_scene", TTR("Close Scene"), KeyModifierMask::CMD_OR_CTRL + KeyModifierMask::SHIFT + Key::W), FILE_CLOSE);
	recent_scenes = memnew(PopupMenu);
	recent_scenes->set_name("RecentScenes");
	file_menu->add_child(recent_scenes);
	recent_scenes->connect("id_pressed", callable_mp(this, &EditorNode::_open_recent_scene));