style(muscript): carry over packedArgs on ExprGroup.optimize

muscript/src/main/java/io/gitlab/jfronny/muscript/ast/dynamic/ExprGroup.java

@@ -83,17 +83,22 @@ public class ExprGroup extends DynamicExpr {
 
     @Override
     public DynamicExpr optimize() {
-        return of(
-                location,
-                Stream.concat(
-                        steps.stream()
-                                .map(Expr::optimize)
-                                .flatMap(Expr::extractSideEffects)
-                                .map(Expr::optimize),
-                        Stream.of(fin.optimize())
-                ).toList(),
-                fork
-        ).asDynamicExpr();
+        List<Expr<?>> exprs = Stream.concat(
+                steps.stream()
+                        .map(Expr::optimize)
+                        .flatMap(Expr::extractSideEffects)
+                        .map(Expr::optimize),
+                Stream.of(fin.optimize())
+        ).toList();
+        if (packedArgs == null) {
+            return of(
+                    location,
+                    exprs,
+                    fork
+            ).asDynamicExpr();
+        } else {
+            return new ExprGroup(location, exprs, packedArgs, fork);
+        }
     }
 
     @Override