### 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)
pick_main_scene->set_meta("from_native", p_from_native); 
	String main_scene = GLOBAL_GET("application/run/main_scene");
	if (main_scene.is_empty()) {
		current_menu_option = -1;
		pick_main_scene->set_text(TTR("No main scene has ever been defined, select one?\nYou can change it later in \"Project Settings\" under the 'application' category."));
		pick_main_scene->popup_centered();
		if (editor_data.get_edited_scene_root()) {
			select_current_scene_button->set_disabled(false);
			select_current_scene_button->grab_focus();
		} else {
			select_current_scene_button->set_disabled(true);
		}
		return false;
	}
	if (!FileAccess::exists(main_scene)) {
		current_menu_option = -1;
		pick_main_scene->set_text(vformat(TTR("Selected scene '%s' does not exist, select a valid one?\nYou can change it later in \"Project Settings\" under the 'application' category."), main_scene));
		pick_main_scene->popup_centered();
		return false;
	}
	if (ResourceLoader::get_resource_type(main_scene) != "PackedScene") {
		current_menu_option = -1;
		pick_main_scene->set_text(vformat(TTR("Selected scene '%s' is not a scene file, select a valid one?\nYou can change it later in \"Project Settings\" under the 'application' category."), main_scene));
		pick_main_scene->popup_centered();
		return false;
	}
	return true;
}
void EditorNode::_immediate_dialog_confirmed() {