Use Delay error directly when casting from data without traces

crates/aiken-lang/src/gen_uplc/builder.rs

@@ -981,7 +981,11 @@ pub fn unknown_data_to_type(term: Term<Name>, field_type: &Type) -> Term<Name> {
             .lambda("__list_data")
             .apply(Term::unlist_data().apply(term)),
         Some(UplcType::Bool) => Term::unwrap_bool_or(term, |result| result, &Term::Error.delay()),
-        Some(UplcType::Unit) => Term::unwrap_void_or(term, |result| result, &Term::Error.delay()),
+        Some(UplcType::Unit) => Term::unwrap_void_or(
+            term.as_var("val", |val| Term::Var(val)),
+            |result| result,
+            &Term::Error.delay(),
+        ),
 
         Some(UplcType::Data) | None => term,
     }