Finalized network related resource in cloud pinyin when it is not used.

[wengxt]

curl 8.9.0 (not link the upstream link here to avoid spamming in github since upstream already fixed it) was causing issue to make event monitoring on curl into busy loop.

However, disable cloudpinyin (with hotkey or from configtool), doesn't work as a mitigation, since we do not do any curl related clean up when it is disabled. When cloudpinyin is disabled, we just simply don't send any new request.

The reason that why it is implemented in this way, is because, in fcitx5 we moved the cloudpinyin's enable/disable from module to engine. Thus module doesn't have a way to track, whether cloudpinyin "may" be used in near future, or not.

We should consider implement something, that can clean up all the resources on cloudpinyin and only initialize them when needed. It only involves a thread creation and some struct initialization in curl, which should be cheap if we don't always keep it.