### Godot version

Beta 17, master

### System information

Windows 11

### Issue description

Godot gets a hard crash while attempting to code-complete for member `const` of a class.

### Steps to reproduce

```GDScript
enum E { V1 }

const e := E
```

And then type a `.` after the last `E`, which triggers code hints/auto-completion for subscripts based on `E` and causes a hard crash.

Does not happen for `var e := E.V1`.

### Minimal reproduction project

See above.
ERR_FAIL_NULL(p_identifier);
	p_identifier->set_datatype(p_identifier_datatype);
	Error err = OK;
	Ref<GDScript> scr = GDScriptCache::get_shallow_script(p_identifier_datatype.script_path, err);
	if (err) {
		push_error(vformat(R"(Error while getting cache for script "%s".)", p_identifier_datatype.script_path), p_identifier);
		return;
	}
	p_identifier->reduced_value = scr->find_class(p_identifier_datatype.class_type->fqcn);
	p_identifier->is_constant = true;
}
void GDScriptAnalyzer::reduce_identifier_from_base(GDScriptParser::IdentifierNode *p_identifier, GDScriptParser::DataType *p_base) {
	if (!p_identifier->get_datatype().has_no_type()) {
		return;
	}
	GDScriptParser::DataType base;
	if (p_base == nullptr) {
		base = type_from_metatype(parser->current_class->get_datatype());
	} else {
		base = *p_base;
	}
	const StringName &name = p_identifier->name;
	if (base.kind == GDScriptParser::DataType::ENUM) {
		if (base.is_meta_type) {