修复自动创建会话没有昵称的bug

core/src/main/java/com/wecloud/im/service/impl/ImMessageServiceImpl.java

@@ -818,7 +818,7 @@ public class ImMessageServiceImpl extends BaseServiceImpl<ImMessageMapper, ImMes
             members.add(receiver);
             // 创建会话
             ServerImConversationCreate conversationCreate = new ServerImConversationCreate();
-            conversationCreate.setName(null);
+            conversationCreate.setName(sender.getNickname());
             conversationCreate.setAttributes(null);
             conversationCreate.setCreator(sender);
             conversationCreate.setMembers(members);