R Shiny + plotly legend in sidebar?

Question

I'd like to put the legend to one of my graphs in the sidebar of my shiny fluid-page. I had two ideas for this:

1. Get the legend grob via ggplotly and put in sidebar or
2. Render a legend with the same colors and no plot in the sidebar.
   Unfortunately I'm not sure how to do either of these.

Any ideas?
Example shiny below.

library(plotly, shiny) 

data <- ChickWeight
ag_data <- aggregate(data$weight,
                     list(time = data$Time, diet = data$Diet),
                     mean)  

ui <- fluidPage(
  
  sidebarPanel("Put Legend Here"),
  mainPanel(
    plotlyOutput("chick_weight")
  )

) # End fluid page

server <- function(input, output) {
  
  output$chick_weight <- renderPlotly({
    plot_ly(
      x = c(ag_data$time),
      y = c(ag_data$x),
      type = "scatter",
      mode = "lines",
      split = c(ag_data$diet),
      showlegend = FALSE
    )
  })
  
} # End server function

shinyApp(ui = ui, server = server)