removing renaming of json Err variant of contract result, too

Author: eshelB

packages/std/src/results/contract_result.rs

@@ -36,7 +36,6 @@ pub enum ContractResult<S> {
     Ok(S),
     /// An error type that every custom error created by contract developers can be converted to.
     /// This could potientially have more structure, but String is the easiest.
-    #[serde(rename = "error")]
     Err(String),
 }