### 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

‮
DictionaryNode *dictionary = alloc_node<DictionaryNode>();
	bool decided_style = false;
	if (!check(GDScriptTokenizer::Token::BRACE_CLOSE)) {
		do {
			if (check(GDScriptTokenizer::Token::BRACE_CLOSE)) {
				
				break;
			}
			
			ExpressionNode *key = parse_expression(false, true); 
			if (key == nullptr) {
				push_error(R"(Expected expression as dictionary key.)");
			}
			if (!decided_style) {
				switch (current.type) {
					case GDScriptTokenizer::Token::COLON:
						dictionary->style = DictionaryNode::PYTHON_DICT;
						break;
					case GDScriptTokenizer::Token::EQUAL:
						dictionary->style = DictionaryNode::LUA_TABLE;
						break;
					default:
						push_error(R"(Expected ":" or "=" after dictionary key.)");