### 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)
int x = (img->get_width() - vp_size) / 2;
			int y = (img->get_height() - vp_size) / 2;
			if (vp_size < preview_size) {
				
				img->crop_from_point(x, y, vp_size, vp_size);
			} else {
				int ratio = vp_size / preview_size;
				int size = preview_size * MAX(1, ratio / 2);
				x = (img->get_width() - size) / 2;
				y = (img->get_height() - size) / 2;
				img->crop_from_point(x, y, size, size);
				img->resize(preview_size, preview_size, Image::INTERPOLATE_LANCZOS);
			}
			img->convert(Image::FORMAT_RGB8);
			
			String temp_path = EditorPaths::get_singleton()->get_cache_dir();
			String cache_base = ProjectSettings::get_singleton()->globalize_path(p_file).md5_text();
			cache_base = temp_path.path_join("resthumb-" + cache_base);
			
			post_process_preview(img);
			img->save_png(cache_base + ".png");
		}
	}
	save.step(TTR("Saving Scene"), 4);
	_save_scene(p_file, p_idx);
	if (!singleton->cmdline_export_mode) {
		EditorResourcePreview::get_singleton()->check_for_invalidation(p_file);
	}
}
bool EditorNode::_validate_scene_recursive(const String &p_filename, Node *p_node) {