ft-manager: add FT's channel class if contact announces to support OOB
ft-manager: add FT's channel class if contact announces to support OOB

freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut,freedesktop-unofficial-mirror/telepathy__telepathy-salut