### 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 < vsplits.size(); i++) {
			bool in_use = dock_slot[i * 2 + 0]->get_tab_count() || dock_slot[i * 2 + 1]->get_tab_count();
			if (in_use) {
				vsplits[i]->show();
			} else {
				vsplits[i]->hide();
			}
		}
		bottom_panel->show();
		if (right_l_vsplit->is_visible() || right_r_vsplit->is_visible()) {
			right_hsplit->show();
		} else {
			right_hsplit->hide();
		}
	}
}
void EditorNode::_restore_floating_dock(const Dictionary &p_dock_dump, Control *p_dock, int p_slot_index) {
	WindowWrapper *wrapper = Object::cast_to<WindowWrapper>(p_dock);
	if (!wrapper) {
		_dock_make_float(p_dock, p_slot_index, false);
		wrapper = floating_docks[floating_docks.size() - 1];
	}
	wrapper->restore_window_from_saved_position(
			p_dock_dump.get("window_rect", Rect2i()),
			p_dock_dump.get("window_screen", -1),
			p_dock_dump.get("window_screen_rect", Rect2i()));
}
void EditorNode::_load_docks_from_config(Ref<ConfigFile> p_layout, const String &p_section) {