Legend position not preserved when converting ggplot2 to plotly #2407

Description

When converting a ggplot2 plot to plotly using ggplotly(), the legend position specified in theme(legend.position=...) is not preserved in the resulting plotly graph. This requires additional layout configuration after conversion.

Reproducible Example

library(ggplot2)
library(plotly)

# Sample data
set.seed(123)
data <- data.frame(
  category = LETTERS[1:10],
  value = runif(10),
  group = factor(rep(1:2, 5))
)

# Create ggplot with specified legend position
p <- ggplot(data) +
  aes(x = category, y = value, fill = group) +
  geom_col() +
  theme(legend.position = "bottom")  # This position is not preserved

# Convert to plotly
p_interactive <- ggplotly(p)

# Current workaround needed
p_interactive <- ggplotly(p) %>%
  layout(
    legend = list(
      orientation = "h",
      x = 0.5,
      y = -0.2,
      xanchor = "center",
      yanchor = "top"
    )
  )

Expected Behavior

The legend position specified in the ggplot2 theme should be automatically translated to the equivalent plotly layout configuration.

Actual Behavior

The legend position from ggplot2 is ignored, and the legend defaults to plotly's default position (right side). Manual configuration using layout() is required to achieve the desired legend position.

Environment Information

• R version: 4.4.2
• The plot is rendered inside a Shiny App

Additional Context

This affects the workflow when converting static ggplot2 visualizations to interactive plotly graphs, requiring additional code to maintain consistent legend positioning. It would be helpful if the conversion process could automatically map ggplot2's legend positions to plotly's layout configurations.