### 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 (owner) {
					Ref<SceneState> ss_inst = owner->get_scene_instance_state();
					if (ss_inst.is_valid()) {
						ss_inst->update_instance_resource(p_instance_path, current_packed_scene);
					}
					owner->set_editable_instance(instantiated_node, is_editable);
				}
				
				for (AdditiveNodeEntry additive_node_entry : addition_list) {
					Node *parent_node = instantiated_node->get_node_or_null(additive_node_entry.parent);
					if (!parent_node) {
						parent_node = current_edited_scene;
					}
					parent_node->add_child(additive_node_entry.node);
					parent_node->move_child(additive_node_entry.node, additive_node_entry.index);
					
					if (additive_node_entry.owner == original_node) {
						additive_node_entry.owner = instantiated_node;
					}
					additive_node_entry.node->set_owner(additive_node_entry.owner);
					
					{
						Node2D *node_2d = Object::cast_to<Node2D>(additive_node_entry.node);
						if (node_2d) {
							node_2d->set_transform(additive_node_entry.transform_2d);
						}
						Node3D *node_3d = Object::cast_to<Node3D>(additive_node_entry.node);
						if (node_3d) {
							node_3d->set_transform(additive_node_entry.transform_3d);
						}