更新 优化部分情况下，多余的uni-id-users查询逻辑

uniCloud/cloudfunctions/uni-im-co/conversation.js

@@ -209,11 +209,14 @@ async function getConversationList({
   let friend_uids = res.data.map(item => item.friend_uid).filter(i => i)
   // 计算请求时间
   startTime = Date.now()
-  let usersInfoRes = await dbJQL.collection('uni-id-users')
+  let usersInfoRes = {data:[]}
+  if (friend_uids.length !== 0){
+    usersInfoRes = await dbJQL.collection('uni-id-users')
       .where(`_id in ${JSON.stringify(friend_uids)}`)
       .field('_id,avatar_file,nickname,realname_auth')
       .limit(friend_uids.length)
       .get()
+  }
   // log请求时间
   // console.error('get user耗时', Date.now() - startTime,startTime)