Update ConversationListAdapter.java

[Yuanarcheannovice]

修复会话列表 删除A会话后，再长按A会话下面其他的会话，下标异常导致闪退或者弹框位置错误

    @Override
    public void onItemRemoved(int position) {
        int itemIndex = getItemIndexInAdapter(position);
        notifyItemRemoved(itemIndex);
         //保证会话下标正常
        notifyItemRangeChanged(itemIndex,mDataSource.size()-position);
    }

    @Override
    public void onItemInserted(int position) {
        int itemIndex = getItemIndexInAdapter(position);
        notifyItemInserted(itemIndex);
        //保证会话下标正常
        notifyItemRangeChanged(itemIndex,mDataSource.size()-position);
    }