### 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)

}
#endif
				result_type.kind = GDScriptParser::DataType::VARIANT;
			}
		}
		if (!valid) {
			push_error(vformat(R"(Cannot find member "%s" in base "%s".)", p_subscript->attribute->name, type_from_metatype(base_type).to_string()), p_subscript->attribute);
			result_type.kind = GDScriptParser::DataType::VARIANT;
		}
	} else {
		if (p_subscript->index == nullptr) {
			return;
		}
		reduce_expression(p_subscript->index);
		if (p_subscript->base->is_constant && p_subscript->index->is_constant) {
			
			bool valid = false;
			Variant value = p_subscript->base->reduced_value.get(p_subscript->index->reduced_value, &valid);
			if (!valid) {
				push_error(vformat(R"(Cannot get index "%s" from "%s".)", p_subscript->index->reduced_value, p_subscript->base->reduced_value), p_subscript->index);
			} else {
				p_subscript->is_constant = true;
				p_subscript->reduced_value = value;
				result_type = type_from_variant(value, p_subscript);
			}
			result_type.kind = GDScriptParser::DataType::VARIANT;
		} else {
			GDScriptParser::DataType base_type = p_subscript->base->get_datatype();
			GDScriptParser::DataType index_type = p_subscript->index->get_datatype();
			if (base_type.is_variant()) {