### 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

‮
push_error(R"(Variant doesn't contain nested types.)", p_type->type_chain[1]);
			return bad_type;
		}
		result.kind = GDScriptParser::DataType::VARIANT;
	} else if (first == SNAME("Object")) {
		
		result.kind = GDScriptParser::DataType::NATIVE;
		result.native_type = SNAME("Object");
	} else if (GDScriptParser::get_builtin_type(first) < Variant::VARIANT_MAX) {
		
		if (p_type->type_chain.size() > 1) {
			push_error(R"(Built-in types don't contain nested types.)", p_type->type_chain[1]);
			return bad_type;
		}
		result.kind = GDScriptParser::DataType::BUILTIN;
		result.builtin_type = GDScriptParser::get_builtin_type(first);
		if (result.builtin_type == Variant::ARRAY) {
			GDScriptParser::DataType container_type = type_from_metatype(resolve_datatype(p_type->container_type));
			if (container_type.kind != GDScriptParser::DataType::VARIANT) {
				result.set_container_element_type(container_type);
			}
		}
	} else if (class_exists(first)) {
		
		result.kind = GDScriptParser::DataType::NATIVE;
		result.native_type = first;
	} else if (ScriptServer::is_global_class(first)) {
		if (parser->script_path == ScriptServer::get_global_class_path(first)) {
			result = parser->head->get_datatype();
		} else {