feat(knowledge): 移除知识库管理中的敏感级别功能

- 注释掉创建知识集表单中的敏感级别选择字段
- 移除知识集详情页面中的敏感级别显示项
- 注释掉相关的敏感级别选项配置常量
- 更新表单布局以保持一致的两列网格结构

frontend/src/pages/KnowledgeManagement/knowledge-management.const.tsx

@@ -66,6 +66,11 @@ export const knowledgeSourceTypeOptions = [
   { label: "文件上传", value: KnowledgeSourceType.FILE_UPLOAD },
 ];
 
+// export const sensitivityOptions = [
+//   { label: "敏感", value: "敏感" },
+//   { label: "不敏感", value: "不敏感" },
+// ];
+
 export type KnowledgeSetView = {
   id: string;
   name: string;