### 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)
ObjectID current_id = editor_history.get_current();
	Object *current_obj = current_id.is_valid() ? ObjectDB::get_instance(current_id) : nullptr;
	Ref<Resource> res = Object::cast_to<Resource>(current_obj);
	if (p_skip_foreign && res.is_valid()) {
		const int current_tab = scene_tabs->get_current_tab();
		if (res->get_path().find("::") > -1 && res->get_path().get_slice("::", 0) != editor_data.get_scene_path(current_tab)) {
			
			current_obj = nullptr;
		}
	}
	bool inspector_only = editor_history.is_current_inspector_only();
	this->current = current_obj;
	if (!current_obj) {
		SceneTreeDock::get_singleton()->set_selected(nullptr);
		InspectorDock::get_inspector_singleton()->edit(nullptr);
		NodeDock::get_singleton()->set_node(nullptr);
		InspectorDock::get_singleton()->update(nullptr);
		hide_unused_editors();
		return;
	}
	
	bool disable_folding = bool(EDITOR_GET("interface/inspector/disable_folding")) || current_obj->is_class("EditorDebuggerRemoteObject");
	if (InspectorDock::get_inspector_singleton()->is_using_folding() == disable_folding) {
		InspectorDock::get_inspector_singleton()->set_use_folding(!disable_folding, false);
	}
	bool is_resource = current_obj->is_class("Resource");