### 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)

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;