### 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

‮
p_identifier->is_constant = true;
					p_identifier->reduced_value = member.constant->initializer->reduced_value;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					p_identifier->constant_source = member.constant;
					return;
				}
				case GDScriptParser::ClassNode::Member::ENUM_VALUE: {
					p_identifier->set_datatype(member.get_datatype());
					p_identifier->is_constant = true;
					p_identifier->reduced_value = member.enum_value.value;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					return;
				}
				case GDScriptParser::ClassNode::Member::ENUM: {
					p_identifier->set_datatype(member.get_datatype());
					p_identifier->is_constant = true;
					p_identifier->reduced_value = member.m_enum->dictionary;
					p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_CONSTANT;
					return;
				}
				case GDScriptParser::ClassNode::Member::VARIABLE: {
					if (is_base && !base.is_meta_type) {
						p_identifier->set_datatype(member.get_datatype());
						p_identifier->source = GDScriptParser::IdentifierNode::MEMBER_VARIABLE;
						p_identifier->variable_source = member.variable;
						member.variable->usages += 1;
						return;
					}
				} break;
				case GDScriptParser::ClassNode::Member::SIGNAL: {