### 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 (is_constant) {
			if (p_assignable->initializer->type == GDScriptParser::Node::ARRAY) {
				const_fold_array(static_cast<GDScriptParser::ArrayNode *>(p_assignable->initializer), true);
			} else if (p_assignable->initializer->type == GDScriptParser::Node::DICTIONARY) {
				const_fold_dictionary(static_cast<GDScriptParser::DictionaryNode *>(p_assignable->initializer), true);
			}
			if (!p_assignable->initializer->is_constant) {
				push_error(vformat(R"(Assigned value for %s "%s" isn't a constant expression.)", p_kind, p_assignable->identifier->name), p_assignable->initializer);
			}
		}
		if (has_specified_type && p_assignable->initializer->is_constant) {
			update_const_expression_builtin_type(p_assignable->initializer, specified_type, "assign");
		}
		GDScriptParser::DataType initializer_type = p_assignable->initializer->get_datatype();
		if (p_assignable->infer_datatype) {
			if (!initializer_type.is_set() || initializer_type.has_no_type() || !initializer_type.is_hard_type()) {
				push_error(vformat(R"(Cannot infer the type of "%s" %s because the value doesn't have a set type.)", p_assignable->identifier->name, p_kind), p_assignable->initializer);
			} else if (initializer_type.kind == GDScriptParser::DataType::BUILTIN && initializer_type.builtin_type == Variant::NIL && !is_constant) {
				push_error(vformat(R"(Cannot infer the type of "%s" %s because the value is "null".)", p_assignable->identifier->name, p_kind), p_assignable->initializer);
			}
		} else {
			if (!initializer_type.is_set()) {
				push_error(vformat(R"(Could not resolve type for %s "%s".)", p_kind, p_assignable->identifier->name), p_assignable->initializer);
			}
		}
		if (!has_specified_type) {
			type = initializer_type;
			if (!type.is_set() || (type.is_hard_type() && type.kind == GDScriptParser::DataType::BUILTIN && type.builtin_type == Variant::NIL && !is_constant)) {
				type.kind = GDScriptParser::DataType::VARIANT;
			}