### Godot version

4.0 beta 10

### System information

Windows 10

### Issue description

Godot crashes when i accidently name 2 items in an enum the same

EDIT:
The editor freeze for some seconds, then both editor- and console-window dissapear

### Steps to reproduce

Write

```gdscript
enum {
    A,
}
```

and then add a second line with another A:

```gdscript
enum {
    A,
    A # <- crash
}
```

Does not always immediatly happen if i copy&paste items.
Does not happen when i change the script in another editor and open the script in Godot.

### Minimal reproduction project

[enum.zip](https://github.com/godotengine/godot/files/10313759/enum.zip)

if (p_source == nullptr && parser->has_class(p_class)) {
		p_source = p_class;
	}
	if (p_class->base_type.is_resolving()) {
		push_error(vformat(R"(Could not resolve class "%s": Cyclic reference.)", type_from_metatype(p_class->get_datatype()).to_string()), p_source);
		return ERR_PARSE_ERROR;
	}
	if (!p_class->base_type.has_no_type()) {
		
		return OK;
	}
	if (!parser->has_class(p_class)) {
		String script_path = p_class->get_datatype().script_path;
		Ref<GDScriptParserRef> parser_ref = get_parser_for(script_path);
		if (parser_ref.is_null()) {
			push_error(vformat(R"(Could not find script "%s".)", script_path), p_source);
			return ERR_PARSE_ERROR;