### 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 (!global_menu || !OS::get_singleton()->has_feature("macos")) {
		
		file_menu->add_separator();
		file_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/file_quit", TTR("Quit"), KeyModifierMask::CMD_OR_CTRL + Key::Q), FILE_QUIT, true);
	}
	project_menu = memnew(PopupMenu);
	project_menu->set_name(TTR("Project"));
	main_menu->add_child(project_menu);
	project_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/project_settings", TTR("Project Settings..."), Key::NONE, TTR("Project Settings")), RUN_SETTINGS);
	project_menu->connect("id_pressed", callable_mp(this, &EditorNode::_menu_option));
	project_menu->add_separator();
	project_menu->add_item(TTR("Version Control"), VCS_MENU);
	project_menu->add_separator();
	project_menu->add_shortcut(ED_SHORTCUT_AND_COMMAND("editor/export", TTR("Export..."), Key::NONE, TTR("Export")), FILE_EXPORT_PROJECT);
#ifndef ANDROID_ENABLED
	project_menu->add_item(TTR("Install Android Build Template..."), FILE_INSTALL_ANDROID_SOURCE);
	project_menu->add_item(TTR("Open User Data Folder"), RUN_USER_DATA_FOLDER);
#endif
	project_menu->add_separator();
	project_menu->add_item(TTR("Customize Engine Build Configuration..."), TOOLS_BUILD_PROFILE_MANAGER);
	project_menu->add_separator();
	tool_menu = memnew(PopupMenu);
	tool_menu->set_name("Tools");
	tool_menu->connect("index_pressed", callable_mp(this, &EditorNode::_tool_menu_option));
	project_menu->add_child(tool_menu);
	project_menu->add_submenu_item(TTR("Tools"), "Tools");
	tool_menu->add_item(TTR("Orphan Resource Explorer..."), TOOLS_ORPHAN_RESOURCES);
	tool_menu->add_item(TTR("Upgrade Mesh Surfaces..."), TOOLS_SURFACE_UPGRADE);
	project_menu->add_separator();
	project_menu->add_shortcut(ED_SHORTCUT("editor/reload_current_project", TTR("Reload Current Project")), RELOAD_CURRENT_PROJECT);