refactor: update prefix usage in knowledge API call

--bug=1057818 --user=刘瑞斌 [知识库]企业版/专业版-知识库详情页-设置-修改任意信息，保存后页面404 https://www.tapd.cn/62980211/s/1721489

ui/src/api/knowledge/knowledge.ts

@@ -252,7 +252,7 @@ const putLarkKnowledge: (
   data: any,
   loading?: Ref<boolean>
 ) => Promise<Result<any>> = (knowledge_id, data, loading) => {
-  return put(`${prefix}/lark/${knowledge_id}`, data, undefined, loading)
+  return put(`${prefix.value}/lark/${knowledge_id}`, data, undefined, loading)
 }
 
 export default {