### 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)
for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
		if (editor_data.get_scene_path(i) == p_path) {
			return true;
		}
	}
	return false;
}
void EditorNode::fix_dependencies(const String &p_for_file) {
	dependency_fixer->edit(p_for_file);
}
int EditorNode::new_scene() {
	int idx = editor_data.add_edited_scene(-1);
	_set_current_scene(idx); 
	
	if (editor_data.get_edited_scene_count() > 1) {
		for (int i = 0; i < editor_data.get_edited_scene_count() - 1; i++) {
			bool unsaved = EditorUndoRedoManager::get_singleton()->is_history_unsaved(editor_data.get_scene_history_id(i));
			if (!unsaved && editor_data.get_scene_path(i).is_empty() && editor_data.get_edited_scene_root(i) == nullptr) {
				editor_data.remove_scene(i);
				idx--;
			}
		}
	}
	editor_data.clear_editor_states();
	scene_tabs->update_scene_tabs();
	return idx;
}
Error EditorNode::load_scene(const String &p_scene, bool p_ignore_broken_deps, bool p_set_inherited, bool p_clear_errors, bool p_force_open_imported, bool p_silent_change_tab) {