Option to remove the white shadow in sankey type diagram

Brief description of the problem
Hi I need to have a cleaner version of sankey diagram but couldn't find the option in API doc.

The dom class name is text-shadow, but in the doc
There's no definition to include/exclude text shadow.

  plot_ly(
    type = "sankey",
    domain = c(
      x =  c(0,1),
      y =  c(0,1)
    ),
    orientation = "h",
    node = node,
    link = link,
    width = 2000,
    height = 3600) %>% 
  layout(
    title = "TBD",
    font = list(
      size = 10,
      color = 'white'
    ),
    plot_bgcolor = 'black',
    paper_bgcolor = 'black'
)

从 sankey 图表入口点和 issue 中描述的 text-shadow DOM 类开始，然后对照 R API 文档检查 layout 和 style 选项。完成标准是用户可以显式地在 sankey 图中包含或排除白色阴影，并且该选项已有文档说明。