【优化】AI 角色分类处理用户角色，为空情况

yudao-module-ai/yudao-module-ai-biz/src/main/java/cn/iocoder/yudao/module/ai/service/model/AiChatRoleServiceImpl.java

@@ -14,6 +14,8 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.stereotype.Service;
 
 import java.util.List;
+import java.util.Objects;
+import java.util.stream.Collectors;
 
 import static cn.iocoder.yudao.framework.common.exception.util.ServiceExceptionUtil.exception;
 import static cn.iocoder.yudao.framework.common.util.collection.CollectionUtils.convertList;
@@ -132,7 +134,7 @@ public class AiChatRoleServiceImpl implements AiChatRoleService {
     @Override
     public List<String> getChatRoleCategoryList() {
         List<AiChatRoleDO> list = chatRoleMapper.selectListGroupByCategory(CommonStatusEnum.ENABLE.getStatus());
-        return convertList(list, AiChatRoleDO::getCategory);
+        return convertList(list.stream().filter(Objects::nonNull).collect(Collectors.toList()), AiChatRoleDO::getCategory);
     }
 
 }