legend.position always 'right' in ggplotly, except when legend.position = 'none'

When plotting a ggplot object using ggplotly, legend.position is always 'right' even if I chose legend.position = 'top' or any of the other options. It only works as it is supposed to when I specify legend.position = 'none' that it actually disappears.

ggplot displays the legend fine.

library(tibble)
library(ggplot2)

df <- tibble(year = c(2000, 2001, 2000, 2001),
             freq = c(3, 4, 2, 9),
             clas = c("A", "A", "B", "B"))

ggplot(df, aes(year, freq, color = clas)) +
  geom_line() +
  theme(legend.position = 'top')

When I try this instead:

library(plotly)

ggplotly(
ggplot(df, aes(year, freq, color = clas)) +
  geom_line() +
  theme(legend.position = 'top')
)

I get the legend on the right, as I show in this shiny app.

Start with the reproducible R example using ggplotly, ggplot2, tibble, and theme(legend.position = 'top'), then compare the rendered legend position with the ggplot output. Done means ggplotly honors top and other supported legend positions while still hiding the legend for legend.position = 'none'.