`sv_ev_room_message()` called `groupchat_log_msg_in()` to log all incoming MUC messages. `cl_ev_send_muc_msg()` calls `groupchat_log_msg_out()`. So messages sent by the user himself was logged two times. Filter the incoming messages and only log the ones not from our occupant jid/nick. Fix https://github.com/profanity-im/profanity/issues/1201