### 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)
if (ProjectSettings::get_singleton()->has_custom_feature("dedicated_server")) {
		audio_driver = NULL_AUDIO_DRIVER;
		display_driver = NULL_DISPLAY_DRIVER;
	}
	GLOBAL_DEF(PropertyInfo(Variant::INT, "network/limits/debugger/max_chars_per_second", PROPERTY_HINT_RANGE, "0, 4096, 1, or_greater"), 32768);
	GLOBAL_DEF(PropertyInfo(Variant::INT, "network/limits/debugger/max_queued_messages", PROPERTY_HINT_RANGE, "0, 8192, 1, or_greater"), 2048);
	GLOBAL_DEF(PropertyInfo(Variant::INT, "network/limits/debugger/max_errors_per_second", PROPERTY_HINT_RANGE, "0, 200, 1, or_greater"), 400);
	GLOBAL_DEF(PropertyInfo(Variant::INT, "network/limits/debugger/max_warnings_per_second", PROPERTY_HINT_RANGE, "0, 200, 1, or_greater"), 400);
	EngineDebugger::initialize(debug_uri, skip_breakpoints, breakpoints, []() {
		if (editor_pid) {
			DisplayServer::get_singleton()->enable_for_stealing_focus(editor_pid);
		}
	});
#ifdef TOOLS_ENABLED
	if (editor) {
		packed_data->set_disabled(true);
		main_args.push_back("--editor");
		if (!init_windowed && !init_fullscreen) {
			init_maximized = true;
			window_mode = DisplayServer::WINDOW_MODE_MAXIMIZED;
		}
	}
	if (!project_manager && !editor) {
		
		project_manager = !found_project && !cmdline_tool;
	}
	if (project_manager) {
		Engine::get_singleton()->set_project_manager_hint(true);
	}
#endif