Default cloud pinyin source "sogou" no longer exist

[Impact] Default cloud pinyin source "sogou" no longer exist, the web api returns 403 for quite some time, so that default value of this module is no longer working.

[Test Case]When using fcitx in zh_CN, install fcitx-module-cloudpinyin, re-login, type a sentence, see if the second candidate is loaded dynamically. Expected behavior is that the secondd candidate is dynamically loaded.

[Regression Potential]It's a simple configuration switch, so there is unlikely to be regression. But users who have already chosen a cloud pinyin supplier may not get everything correct after installing this update because user config will overwrite system default.