### 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

‮
ERR_FAIL_COND_MSG(!parser->valid_annotations.has(p_annotation->name), vformat(R"(Annotation "%s" not found to validate.)", p_annotation->name));
	const MethodInfo &annotation_info = parser->valid_annotations[p_annotation->name].info;
	const List<PropertyInfo>::Element *E = annotation_info.arguments.front();
	for (int i = 0; i < p_annotation->arguments.size(); i++) {
		GDScriptParser::ExpressionNode *argument = p_annotation->arguments[i];
		const PropertyInfo &argument_info = E->get();
		if (E->next() != nullptr) {
			E = E->next();
		}
		reduce_expression(argument);
		if (!argument->is_constant) {
			push_error(vformat(R"(Argument %d of annotation "%s" isn't a constant expression.)", i + 1, p_annotation->name), argument);
			return;
		}
		Variant value = argument->reduced_value;
		if (value.get_type() != argument_info.type) {
#ifdef DEBUG_ENABLED
			if (argument_info.type == Variant::INT && value.get_type() == Variant::FLOAT) {
				parser->push_warning(argument, GDScriptWarning::NARROWING_CONVERSION);
			}
#endif
			if (!Variant::can_convert_strict(value.get_type(), argument_info.type)) {
				push_error(vformat(R"(Invalid argument for annotation "%s": argument %d should be "%s" but is "%s".)", p_annotation->name, i + 1, Variant::get_type_name(argument_info.type), argument->get_datatype().to_string()), argument);
				return;
			}
			Variant converted_to;