empathy_tp_chat_is_invited: use new channel group API
empathy_tp_chat_is_invited: use new channel group API

https://bugzilla.gnome.org/show_bug.cgi?id=675229

GNOME/telepathy-account-widgets,GNOME/telepathy-account-widgets,Distrotech/telepathy-account-widgets,Distrotech/telepathy-account-widgets,GNOME/telepathy-account-widgets