### 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

‮
Error err = resolve_class_inheritance(look_class, p_class);
							if (err) {
								return err;
							}
						}
						base = look_class->get_datatype();
						found = true;
						break;
					}
					if (look_class->has_member(name)) {
						resolve_class_member(look_class, name, p_class);
						base = look_class->get_member(name).get_datatype();
						found = true;
						break;
					}
				}
				if (!found) {
					push_error(vformat(R"(Could not find base class "%s".)", name), p_class);
					return ERR_PARSE_ERROR;
				}
			}
		}
		for (int index = extends_index; index < p_class->extends.size(); index++) {
			if (base.kind != GDScriptParser::DataType::CLASS) {
				push_error(R"(Super type "%s" is not a GDScript. Cannot get nested types.)", p_class);
				return ERR_PARSE_ERROR;
			}
			
			GDScriptParser::IdentifierNode *id = parser->alloc_node<GDScriptParser::IdentifierNode>();
			id->name = p_class->extends[index];