MatrixClient stores HS when logging in / registering, but not when creating with token

When a client instance logs in / registers, the response contains, among other things, a home_server field. Currently, this information is stored as a .hs member of the instance. However, if the MatrixClient is created with an exiting token, no such registration/login takes plave, hence no response is received, and the instance doesn't set this member -- which means that code can't rely on its being there.

At the moment, this information isn't used anywhere in the code, so probably the best thing to do is to just remove it.

首先定位 MatrixClient 类及其登录、注册和基于令牌的初始化路径。搜索 .hs 成员，并确认它未被使用，然后再移除不一致的存储；运行现有测试套件，以验证客户端创建和身份验证行为仍然正常。