### 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)
gui_base->add_child(file_export_lib);
	file_script = memnew(EditorFileDialog);
	file_script->set_title(TTR("Open & Run a Script"));
	file_script->set_access(EditorFileDialog::ACCESS_FILESYSTEM);
	file_script->set_file_mode(EditorFileDialog::FILE_MODE_OPEN_FILE);
	List<String> sexts;
	ResourceLoader::get_recognized_extensions_for_type("Script", &sexts);
	for (const String &E : sexts) {
		file_script->add_filter("*." + E);
	}
	gui_base->add_child(file_script);
	file_script->connect("file_selected", callable_mp(this, &EditorNode::_dialog_action));
	file_menu->connect("id_pressed", callable_mp(this, &EditorNode::_menu_option));
	file_menu->connect("about_to_popup", callable_mp(this, &EditorNode::_update_file_menu_opened));
	file_menu->connect("popup_hide", callable_mp(this, &EditorNode::_update_file_menu_closed));
	settings_menu->connect("id_pressed", callable_mp(this, &EditorNode::_menu_option));
	file->connect("file_selected", callable_mp(this, &EditorNode::_dialog_action));
	file_templates->connect("file_selected", callable_mp(this, &EditorNode::_dialog_action));
	audio_preview_gen = memnew(AudioStreamPreviewGenerator);
	add_child(audio_preview_gen);
	add_editor_plugin(memnew(DebuggerEditorPlugin(debug_menu)));
	disk_changed = memnew(ConfirmationDialog);
	{
		VBoxContainer *vbc = memnew(VBoxContainer);
		disk_changed->add_child(vbc);
		Label *dl = memnew(Label);
		dl->set_text(TTR("The following files are newer on disk.\nWhat action should be taken?"));
		vbc->add_child(dl);
		disk_changed_list = memnew(Tree);
		vbc->add_child(disk_changed_list);