### 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

‮
builtin_types["Signal"] = Variant::SIGNAL;
		builtin_types["Array"] = Variant::ARRAY;
		builtin_types["PackedByteArray"] = Variant::PACKED_BYTE_ARRAY;
		builtin_types["PackedInt32Array"] = Variant::PACKED_INT32_ARRAY;
		builtin_types["PackedInt64Array"] = Variant::PACKED_INT64_ARRAY;
		builtin_types["PackedFloat32Array"] = Variant::PACKED_FLOAT32_ARRAY;
		builtin_types["PackedFloat64Array"] = Variant::PACKED_FLOAT64_ARRAY;
		builtin_types["PackedStringArray"] = Variant::PACKED_STRING_ARRAY;
		builtin_types["PackedVector2Array"] = Variant::PACKED_VECTOR2_ARRAY;
		builtin_types["PackedVector3Array"] = Variant::PACKED_VECTOR3_ARRAY;
		builtin_types["PackedColorArray"] = Variant::PACKED_COLOR_ARRAY;
		
		if (builtin_types.size() != Variant::VARIANT_MAX - 1) {
			ERR_PRINT("Outdated parser: amount of built-in types don't match the amount of types in Variant.");
		}
	}
	if (builtin_types.has(p_type)) {
		return builtin_types[p_type];
	}
	return Variant::VARIANT_MAX;
}
void GDScriptParser::cleanup() {
	builtin_types.clear();
}
void GDScriptParser::get_annotation_list(List<MethodInfo> *r_annotations) const {
	for (const KeyValue<StringName, AnnotationInfo> &E : valid_annotations) {
		r_annotations->push_back(E.value.info);
	}
}
bool GDScriptParser::annotation_exists(const String &p_annotation_name) const {