Apply suggestion from @Copilot

Co-authored-by: Copilot <[email protected]>

Author: winterhazel

server/src/main/java/com/cloud/server/ManagementServerImpl.java

@@ -1280,7 +1280,7 @@ protected void validateEventOperationParameters(List<Long> ids, String type, Dat
             throw new InvalidParameterValueException("Either 'ids', 'type' or 'enddate' must be specified.");
         }
         if (startDate != null && endDate == null) {
-            throw new InvalidParameterValueException("'startdate' must be specified with 'enddate' parameter.");
+            throw new InvalidParameterValueException("'enddate' must be specified when 'startdate' parameter is provided.");
         }
     }