[Feature request]: change height sizing policy of plotly htmlwidget to 100%

Can we change the default widget height sizing policy set in as_widget to 100%. Right now it is 400px and this makes it hard to make a plot to fill its container along the height.

For example, I am hoping to use the following simplified example to change my plot to height 5in. It does not work (for me), because the style of the resulting htmlwidget is set to the default "400px"

tags$div(style="width: 100%; height: 5in", 
  plot_ly(x=1, y=1, type="scatter", mode="markers")
)

The following on the other hand does the job.

tags$div(style="width: 100%; height: 5in", 
   plot_ly(x=1, y=1, type="scatter", mode="markers") %T>% {
     .$sizingPolicy$defaultHeight<-"100%"
 }
)

It seems to me that a default height of "100%", like the default for width, makes more sense (allowing for the container to control the size) than the arbitrary "400px" used right now.

I really would like to control the height of my plots in a R markdown html document and this was the only solution I could come up with: R plotly seems to deal fine with "px" units, but setting inches and % did not work. Perhaps I am missing something...

Start at the as_widget entry point and inspect how the default sizingPolicy height is assigned. Reproduce the tags$div example with a 5in container, then verify that the widget uses the container height when the default height is 100%.