### 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)
return tab_closing_menu_option == FILE_QUIT || tab_closing_menu_option == RUN_PROJECT_MANAGER || tab_closing_menu_option == RELOAD_CURRENT_PROJECT;
}
void EditorNode::_scene_tab_closed(int p_tab) {
	current_menu_option = SCENE_TAB_CLOSE;
	tab_closing_idx = p_tab;
	Node *scene = editor_data.get_edited_scene_root(p_tab);
	if (!scene) {
		_discard_changes();
		return;
	}
	String scene_filename = scene->get_scene_file_path();
	String unsaved_message;
	if (EditorUndoRedoManager::get_singleton()->is_history_unsaved(editor_data.get_scene_history_id(p_tab))) {
		if (scene_filename.is_empty()) {
			unsaved_message = TTR("This scene was never saved.");
		} else {
			
			
			
			const uint64_t last_modified_seconds = Time::get_singleton()->get_unix_time_from_system() - MAX(started_timestamp, FileAccess::get_modified_time(scene->get_scene_file_path()));
			String last_modified_string;
			if (last_modified_seconds < 120) {
				last_modified_string = vformat(TTRN("%d second ago", "%d seconds ago", last_modified_seconds), last_modified_seconds);
			} else if (last_modified_seconds < 7200) {