ggplot2::sec_axis is unsupported

Hello!

When I use ggplot2::scale_y_continuous(sec.axis = ggplot2::sec_axis(~ . / scale_factor)) like this, I discovered that plotly does not support this function. Providing support for this function would greatly assist developers like myself who are accustomed to ggplot but wish to utilise plotly's interactive capabilities.

Thanks.

首先复现 ggplot2::scale_y_continuous(sec.axis = ggplot2::sec_axis(~ . / scale_factor)) 示例，并检查 plotly.R 如何处理 ggplot2 的 scales。定义次坐标轴的预期行为，并验证该示例是否能在交互式图表中正确渲染；issue 未指定要运行的文件或测试。