Update union variant serialization

Author: chardoncs

src/base/value.rs

@@ -897,12 +897,7 @@ impl serde::Serialize for BasicValue {
             BasicValue::TimeDelta(v) => serializer.serialize_str(&v.to_string()),
             BasicValue::Json(v) => v.serialize(serializer),
             BasicValue::Vector(v) => v.serialize(serializer),
-            BasicValue::UnionVariant { tag_id, value } => {
-                let mut s = serializer.serialize_tuple(2)?;
-                s.serialize_element(tag_id)?;
-                s.serialize_element(value)?;
-                s.end()
-            }
+            BasicValue::UnionVariant { value, .. } => value.serialize(serializer),
         }
     }
 }