[Improvement][alert plugin]fix alert massage (#4880)

* fix alert massage
Co-authored-by: N李巨丰 <lijf@2345.com>

dolphinscheduler-alert-plugin/dolphinscheduler-alert-script/src/main/java/org/apache/dolphinscheduler/plugin/alert/script/ScriptAlertChannel.java

@@ -34,7 +34,7 @@ public class ScriptAlertChannel implements AlertChannel {
         AlertData alertData = alertinfo.getAlertData();
         Map<String, String> paramsMap = alertinfo.getAlertParams();
         if (null == paramsMap) {
-            return new AlertResult("false", "ding talk params is null");
+            return new AlertResult("false", "script params is null");
         }
         return new ScriptSender(paramsMap).sendScriptAlert(alertData.getTitle(),alertData.getContent());
     }