### 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

‮
if (signal->parameters_indices.has(parameter->identifier->name)) {
				push_error(vformat(R"(Parameter with name "%s" was already declared for this signal.)", parameter->identifier->name));
			} else {
				signal->parameters_indices[parameter->identifier->name] = signal->parameters.size();
				signal->parameters.push_back(parameter);
			}
		} while (match(GDScriptTokenizer::Token::COMMA) && !is_at_end());
		pop_multiline();
		consume(GDScriptTokenizer::Token::PARENTHESIS_CLOSE, R"*(Expected closing ")" after signal parameters.)*");
	}
	complete_extents(signal);
	end_statement("signal declaration");
	return signal;
}
GDScriptParser::EnumNode *GDScriptParser::parse_enum() {
	EnumNode *enum_node = alloc_node<EnumNode>();
	bool named = false;
	if (check(GDScriptTokenizer::Token::IDENTIFIER)) {
		advance();
		enum_node->identifier = parse_identifier();
		named = true;
	}
	push_multiline(true);
	consume(GDScriptTokenizer::Token::BRACE_OPEN, vformat(R"(Expected "{" after %s.)", named ? "enum name" : R"("enum")"));
	HashMap<StringName, int> elements;
#ifdef DEBUG_ENABLED
	List<MethodInfo> gdscript_funcs;
	GDScriptLanguage::get_singleton()->get_public_functions(&gdscript_funcs);
#endif
	do {