### 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)
InspectorDock::get_inspector_singleton()->update_tree();
}
void EditorNode::_select_default_main_screen_plugin() {
	if (EDITOR_3D < main_editor_buttons.size() && main_editor_buttons[EDITOR_3D]->is_visible()) {
		
		editor_select(EDITOR_3D);
		return;
	}
	
	
	for (int i = 0; i < main_editor_buttons.size(); i++) {
		Button *editor_button = main_editor_buttons[i];
		if (editor_button->is_visible()) {
			editor_select(i);
			return;
		}
	}
	editor_select(-1);
}
void EditorNode::_update_theme(bool p_skip_creation) {
	if (!p_skip_creation) {
		theme = create_custom_theme(theme);
		DisplayServer::set_early_window_clear_color_override(true, theme->get_color(SNAME("background"), EditorStringName(Editor)));
	}
	List<Ref<Theme>> editor_themes;
	editor_themes.push_back(theme);
	editor_themes.push_back(ThemeDB::get_singleton()->get_default_theme());
	ThemeContext *node_tc = ThemeDB::get_singleton()->get_theme_context(this);
	if (node_tc) {