### 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)
ClassDB::bind_method("update_autoload", &EditorAutoloadSettings::update_autoload);
	ClassDB::bind_method("autoload_add", &EditorAutoloadSettings::autoload_add);
	ClassDB::bind_method("autoload_remove", &EditorAutoloadSettings::autoload_remove);
	ADD_SIGNAL(MethodInfo("autoload_changed"));
}
EditorAutoloadSettings::EditorAutoloadSettings() {
	ProjectSettings::get_singleton()->add_hidden_prefix("autoload/");
	
	List<PropertyInfo> props;
	ProjectSettings::get_singleton()->get_property_list(&props);
	for (const PropertyInfo &pi : props) {
		if (!pi.name.begins_with("autoload/")) {
			continue;
		}
		String name = pi.name.get_slice("/", 1);
		String scr_path = GLOBAL_GET(pi.name);
		if (name.is_empty()) {
			continue;
		}
		AutoloadInfo info;
		info.is_singleton = scr_path.begins_with("*");
		if (info.is_singleton) {
			scr_path = scr_path.substr(1, scr_path.length());
		}
		info.name = name;
		info.path = scr_path;
		info.order = ProjectSettings::get_singleton()->get_order(pi.name);
		if (info.is_singleton) {