### 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)
undo_redo->create_action(TTR("Rename Autoload"));
		undo_redo->add_do_property(ProjectSettings::get_singleton(), name, scr_path);
		undo_redo->add_do_method(ProjectSettings::get_singleton(), "set_order", name, order);
		undo_redo->add_do_method(ProjectSettings::get_singleton(), "clear", selected_autoload);
		undo_redo->add_undo_property(ProjectSettings::get_singleton(), selected_autoload, scr_path);
		undo_redo->add_undo_method(ProjectSettings::get_singleton(), "set_order", selected_autoload, order);
		undo_redo->add_undo_method(ProjectSettings::get_singleton(), "clear", name);
		undo_redo->add_do_method(this, "call_deferred", "update_autoload");
		undo_redo->add_undo_method(this, "call_deferred", "update_autoload");
		undo_redo->add_do_method(this, "emit_signal", autoload_changed);
		undo_redo->add_undo_method(this, "emit_signal", autoload_changed);
		undo_redo->commit_action();
		selected_autoload = name;
	} else if (column == 2) {
		updating_autoload = true;
		bool checked = ti->is_checked(2);
		String base = "autoload/" + ti->get_text(0);
		int order = ProjectSettings::get_singleton()->get_order(base);
		String scr_path = GLOBAL_GET(base);
		if (scr_path.begins_with("*")) {
			scr_path = scr_path.substr(1, scr_path.length());
		}
		
		if (checked) {
			scr_path = "*" + scr_path;
		}
		undo_redo->create_action(TTR("Toggle Autoload Globals"));
		undo_redo->add_do_property(ProjectSettings::get_singleton(), base, scr_path);
		undo_redo->add_undo_property(ProjectSettings::get_singleton(), base, GLOBAL_GET(base));
		undo_redo->add_do_method(ProjectSettings::get_singleton(), "set_order", base, order);