### 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)
break;
				}
				if (save_each) {
					tab_closing_menu_option = current_menu_option;
					for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
						tabs_to_close.push_back(editor_data.get_scene_path(i));
					}
					_proceed_closing_scene_tabs();
				} else {
					String unsaved_scenes;
					int i = _next_unsaved_scene(true, 0);
					while (i != -1) {
						unsaved_scenes += "\n            " + editor_data.get_edited_scene_root(i)->get_scene_file_path();
						i = _next_unsaved_scene(true, ++i);
					}
					if (p_option == RELOAD_CURRENT_PROJECT) {
						save_confirmation->set_ok_button_text(TTR("Save & Reload"));
						save_confirmation->set_text(TTR("Save changes to the following scene(s) before reloading?") + unsaved_scenes);
					} else {
						save_confirmation->set_ok_button_text(TTR("Save & Quit"));
						save_confirmation->set_text((p_option == FILE_QUIT ? TTR("Save changes to the following scene(s) before quitting?") : TTR("Save changes to the following scene(s) before opening Project Manager?")) + unsaved_scenes);
					}
					save_confirmation->reset_size();
					save_confirmation->popup_centered();
				}
				DisplayServer::get_singleton()->window_request_attention();
				break;
			}
			_save_external_resources();
			_discard_changes();