### Godot version

4.0 Beta10

### System information

Windows 10, Vulkan, GTX1060

### Issue description

`PropertyTweener`'s methods' return value are not discarded and effect the unary operator at next line.

In Editor:
![in_editor](https://user-images.githubusercontent.com/61624558/210715100-04bdf283-7954-4be3-94ca-338987b24c5b.png)


In cpp:
![in_cpp](https://user-images.githubusercontent.com/61624558/210715127-519f6d54-fc15-468f-9aca-ba7d387a5a7b.png)


### Steps to reproduce

Just run the Minimal reproduction project.

### Minimal reproduction project

[Bug Report.zip](https://github.com/godotengine/godot/files/10349829/Bug.Report.zip)

Ref<GDScriptParserRef> singl_parser = get_parser_for(autoload.path);
				if (singl_parser.is_valid()) {
					Error err = singl_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
					if (err == OK) {
						result = type_from_metatype(singl_parser->get_parser()->head->get_datatype());
					}
				}
			} else if (ResourceLoader::get_resource_type(autoload.path) == "PackedScene") {
				if (GDScriptLanguage::get_singleton()->has_any_global_constant(name)) {
					Variant constant = GDScriptLanguage::get_singleton()->get_any_global_constant(name);
					Node *node = Object::cast_to<Node>(constant);
					if (node != nullptr) {
						Ref<GDScript> scr = node->get_script();
						if (scr.is_valid()) {
							Ref<GDScriptParserRef> singl_parser = get_parser_for(scr->get_script_path());
							if (singl_parser.is_valid()) {
								Error err = singl_parser->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
								if (err == OK) {
									result = type_from_metatype(singl_parser->get_parser()->head->get_datatype());
								}
							}
						}
					}
				}
			}
			result.is_constant = true;
			p_identifier->set_datatype(result);
			return;
		}
	}