【功能优化】工作流：流程详情的重构 50%：梳理整体结构

yudao-framework/yudao-common/src/main/java/cn/iocoder/yudao/framework/common/util/collection/CollectionUtils.java

@@ -332,7 +332,7 @@ public class CollectionUtils {
     }
 
     public static <T> List<T> newArrayList(List<List<T>> list) {
-        return list.stream().flatMap(Collection::stream).collect(Collectors.toList());
+        return list.stream().filter(Objects::nonNull).flatMap(Collection::stream).collect(Collectors.toList());
     }
 
 }