### Godot version

3b086aa06

### System information

ArchLinux x11

### Issue description

```gdscript
extends Node

@export_group("My Properties")
@export var number = 3
@export var string = ""

@export_group("Prefixed Properties", "prefix_")
@export var prefix_number = 3
@export var prefix_string = ""

@export_group("", "")
@export var ungrouped_number = 3
```

![image](https://user-images.githubusercontent.com/70787919/214983963-528c415b-745b-47fc-9777-36ebe31a3060.png)


### Steps to reproduce

- create script
- @export_group
- go inspector

### Minimal reproduction project

‮
#include "gdscript_parser.h"
#include "core/config/project_settings.h"
#include "core/io/file_access.h"
#include "core/io/resource_loader.h"
#include "core/math/math_defs.h"
#include "gdscript.h"
#include "scene/main/multiplayer_api.h"
#ifdef DEBUG_ENABLED
#include "core/os/os.h"
#include "core/string/string_builder.h"
#include "gdscript_warning.h"
#include "servers/text_server.h"
#endif 
#ifdef TOOLS_ENABLED
#include "editor/editor_settings.h"
#endif 
static HashMap<StringName, Variant::Type> builtin_types;
Variant::Type GDScriptParser::get_builtin_type(const StringName &p_type) {