remove more needless String conversions

src/client/result/ResultParser.rs

@@ -300,9 +300,7 @@ pub fn urlDecode(encoded: &str) -> Result<String, Exceptions> {
     if let Ok(decoded) = decode(encoded) {
         Ok(decoded.to_string())
     } else {
-        Err(Exceptions::illegalState(String::from(
-            "UnsupportedEncodingException",
-        )))
+        Err(Exceptions::illegalState("UnsupportedEncodingException"))
     }
 }