### 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)
Ref<PackedScene> scn;
			scn.instantiate();
			scn->set_path(info.path);
			scn->reload_from_file();
			ERR_CONTINUE_MSG(!scn.is_valid(), vformat("Can't autoload: %s.", info.path));
			if (scn.is_valid()) {
				n = scn->instantiate();
			}
		} else {
			Ref<Resource> res = ResourceLoader::load(info.path);
			ERR_CONTINUE_MSG(res.is_null(), vformat("Can't autoload: %s.", info.path));
			Ref<Script> scr = res;
			if (scr.is_valid()) {
				StringName ibt = scr->get_instance_base_type();
				bool valid_type = ClassDB::is_parent_class(ibt, "Node");
				ERR_CONTINUE_MSG(!valid_type, vformat("Script does not inherit from Node: %s.", info.path));
				Object *obj = ClassDB::instantiate(ibt);
				ERR_CONTINUE_MSG(!obj, vformat("Cannot instance script for Autoload, expected 'Node' inheritance, got: %s.", ibt));
				n = Object::cast_to<Node>(obj);
				n->set_script(scr);
			}
		}
		ERR_CONTINUE_MSG(!n, vformat("Path in autoload not a node or script: %s.", info.path));
		n->set_name(info.name);
		for (int i = 0; i < ScriptServer::get_language_count(); i++) {
			ScriptServer::get_language(i)->add_global_constant(info.name, n);
		}
	}
}
void init_language(const String &p_base_path) {