If an item is added, the corresponding code should be wrapped with
beginInsertRows() and endInsertRows(), otherwise proxy or filter models
can end up with corrupted internal state.
m_members.insert() in refreshMember() should be unnecessary because
if pos is not the same as m_members.size(), then it means there's already
a member.id() item in the member list.
(cherry picked from commit 161815acff)
Co-authored-by: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
