### 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)
disk_changed_list->set_v_size_flags(Control::SIZE_EXPAND_FILL);
		disk_changed->connect("confirmed", callable_mp(this, &EditorNode::_reload_modified_scenes));
		disk_changed->connect("confirmed", callable_mp(this, &EditorNode::_reload_project_settings));
		disk_changed->set_ok_button_text(TTR("Reload"));
		disk_changed->add_button(TTR("Resave"), !DisplayServer::get_singleton()->get_swap_cancel_ok(), "resave");
		disk_changed->connect("custom_action", callable_mp(this, &EditorNode::_resave_scenes));
	}
	gui_base->add_child(disk_changed);
	add_editor_plugin(memnew(AnimationPlayerEditorPlugin));
	add_editor_plugin(memnew(AnimationTrackKeyEditEditorPlugin));
	add_editor_plugin(memnew(CanvasItemEditorPlugin));
	add_editor_plugin(memnew(Node3DEditorPlugin));
	add_editor_plugin(memnew(ScriptEditorPlugin));
	EditorAudioBuses *audio_bus_editor = EditorAudioBuses::register_editor();
	ScriptTextEditor::register_editor(); 
	TextEditor::register_editor();
	if (AssetLibraryEditorPlugin::is_available()) {
		add_editor_plugin(memnew(AssetLibraryEditorPlugin));
	} else {
		print_verbose("Asset Library not available (due to using Web editor, or SSL support disabled).");
	}
	
	raise_bottom_panel_item(AnimationPlayerEditor::get_singleton());
	add_editor_plugin(VersionControlEditorPlugin::get_singleton());
	vcs_actions_menu = VersionControlEditorPlugin::get_singleton()->get_version_control_actions_panel();
	vcs_actions_menu->set_name("Version Control");
	vcs_actions_menu->connect("index_pressed", callable_mp(this, &EditorNode::_version_control_menu_option));
	vcs_actions_menu->add_item(TTR("Create Version Control Metadata..."), RUN_VCS_METADATA);
	vcs_actions_menu->add_item(TTR("Version Control Settings..."), RUN_VCS_SETTINGS);
	project_menu->add_child(vcs_actions_menu);