### 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)
ProjectSettings::get_singleton()->setup(ProjectSettings::get_singleton()->get_resource_path(), String(), true);
}
void EditorNode::_vp_resized() {
}
void EditorNode::_titlebar_resized() {
	DisplayServer::get_singleton()->window_set_window_buttons_offset(Vector2i(title_bar->get_global_position().y + title_bar->get_size().y / 2, title_bar->get_global_position().y + title_bar->get_size().y / 2), DisplayServer::MAIN_WINDOW_ID);
	const Vector3i &margin = DisplayServer::get_singleton()->window_get_safe_title_margins(DisplayServer::MAIN_WINDOW_ID);
	if (left_menu_spacer) {
		int w = (gui_base->is_layout_rtl()) ? margin.y : margin.x;
		left_menu_spacer->set_custom_minimum_size(Size2(w, 0));
	}
	if (right_menu_spacer) {
		int w = (gui_base->is_layout_rtl()) ? margin.x : margin.y;
		right_menu_spacer->set_custom_minimum_size(Size2(w, 0));
	}
	if (title_bar) {
		title_bar->set_custom_minimum_size(Size2(0, margin.z - title_bar->get_global_position().y));
	}
}
void EditorNode::_version_button_pressed() {
	DisplayServer::get_singleton()->clipboard_set(version_btn->get_meta(META_TEXT_TO_COPY));
}
void EditorNode::_update_undo_redo_allowed() {
	EditorUndoRedoManager *undo_redo = EditorUndoRedoManager::get_singleton();
	file_menu->set_item_disabled(file_menu->get_item_index(EDIT_UNDO), !undo_redo->has_undo());
	file_menu->set_item_disabled(file_menu->get_item_index(EDIT_REDO), !undo_redo->has_redo());
}
void EditorNode::_node_renamed() {