Fix computed properties of KCL objects (#3246)

* Fix computed properties of KCL objects

Fixes https://github.com/KittyCAD/modeling-app/issues/3201

* Incorporate Jon's feedback

src/wasm-lib/tests/executor/main.rs

@@ -38,6 +38,13 @@ async fn kcl_test_lego() {
     assert_out("lego", &result);
 }
 
+#[tokio::test(flavor = "multi_thread")]
+async fn kcl_test_computed_var() {
+    let code = kcl_input!("computed_var");
+    let result = execute_and_snapshot(code, UnitLength::Mm).await.unwrap();
+    assert_out("computed_var", &result);
+}
+
 #[tokio::test(flavor = "multi_thread")]
 async fn kcl_test_pipe_as_arg() {
     let code = kcl_input!("pipe_as_arg");