### 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)
TTR("The current scene has unsaved changes.\nReload the saved scene anyway? This action cannot be undone."));
				confirmation->popup_centered();
				break;
			}
			int cur_idx = editor_data.get_edited_scene();
			_remove_edited_scene();
			Error err = load_scene(filename);
			if (err != OK) {
				ERR_PRINT("Failed to load scene");
			}
			editor_data.move_edited_scene_to_index(cur_idx);
			EditorUndoRedoManager::get_singleton()->clear_history(false, editor_data.get_current_edited_scene_history_id());
			scene_tabs->set_current_tab(cur_idx);
		} break;
		case FILE_SHOW_IN_FILESYSTEM: {
			String path = editor_data.get_scene_path(editor_data.get_edited_scene());
			if (!path.is_empty()) {
				FileSystemDock::get_singleton()->navigate_to_path(path);
			}
		} break;
		case RUN_SETTINGS: {
			project_settings_editor->popup_project_settings();
		} break;
		case FILE_INSTALL_ANDROID_SOURCE: {
			if (p_confirmed) {
				export_template_manager->install_android_template();
			} else {
				if (DirAccess::exists("res:android/build")) {
					remove_android_build_template->popup_centered();
				} else if (export_template_manager->can_install_android_template()) {