### 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)
while (!eta.done.is_set()) {
		{
			MutexLock lock(eta.execute_output_mutex);
			if (prev_len != eta.output.length()) {
				String to_add = eta.output.substr(prev_len, eta.output.length());
				prev_len = eta.output.length();
				execute_outputs->add_text(to_add);
				DisplayServer::get_singleton()->process_events(); 
				Main::iteration();
			}
		}
		OS::get_singleton()->delay_usec(1000);
	}
	eta.execute_output_thread.wait_to_finish();
	execute_outputs->add_text("\nExit Code: " + itos(eta.exitcode));
	if (execute_output_dialog) {
		if (p_close_on_errors && eta.exitcode != 0) {
			execute_output_dialog->hide();
		}
		if (p_close_on_ok && eta.exitcode == 0) {
			execute_output_dialog->hide();
		}
		execute_output_dialog->get_ok_button()->set_disabled(false);
	}
	if (r_output) {
		*r_output = eta.output;
	}
	return eta.exitcode;
}
EditorNode::EditorNode() {