conversationmodel: fix one to one with self
conversationmodel: fix one to one with self

https://git.jami.net/savoirfairelinux/jami-client-qt/-/issues/455

Change-Id: Ife21f239d1edbd8b49e4976141cc22de2b1fb73d

savoirfairelinux/ring-lrc,savoirfairelinux/ring-lrc,savoirfairelinux/ring-lrc,savoirfairelinux/ring-lrc,savoirfairelinux/ring-lrc