### 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 (p_assignable->infer_datatype || is_constant) {
				type.type_source = GDScriptParser::DataType::ANNOTATED_INFERRED;
			} else {
				type.type_source = GDScriptParser::DataType::INFERRED;
			}
		} else if (!specified_type.is_variant()) {
			if (initializer_type.is_variant() || !initializer_type.is_hard_type()) {
				mark_node_unsafe(p_assignable->initializer);
				p_assignable->use_conversion_assign = true;
				if (!initializer_type.is_variant() && !is_type_compatible(specified_type, initializer_type, true, p_assignable->initializer)) {
					downgrade_node_type_source(p_assignable->initializer);
				}
			} else if (!is_type_compatible(specified_type, initializer_type, true, p_assignable->initializer)) {
				if (!is_constant && is_type_compatible(initializer_type, specified_type)) {
					mark_node_unsafe(p_assignable->initializer);
					p_assignable->use_conversion_assign = true;
				} else {
					push_error(vformat(R"(Cannot assign a value of type %s to %s "%s" with specified type %s.)", initializer_type.to_string(), p_kind, p_assignable->identifier->name, specified_type.to_string()), p_assignable->initializer);
				}
#ifdef DEBUG_ENABLED
			} else if (specified_type.builtin_type == Variant::INT && initializer_type.builtin_type == Variant::FLOAT) {
				parser->push_warning(p_assignable->initializer, GDScriptWarning::NARROWING_CONVERSION);
#endif
			}
		}
	}
	type.is_constant = is_constant;
	p_assignable->set_datatype(type);
}
void GDScriptAnalyzer::resolve_variable(GDScriptParser::VariableNode *p_variable, bool p_is_local) {