title: ggplotly ignores "linetype" aesthetic of geom_bar
body: <p>How to make <code>plotly::ggplotly</code> correctly render/print linetypes when using ggplot2 <code>geom_bar</code>?</p>
  
  <p>Here is a reproductible exemple:</p>
  
  <pre><code>library(tidyverse)
  library(plotly)
  
  # this shows the problem
  static_plot = ggplot(data = mtcars, aes(x = rownames(mtcars), y = mpg, linetype=as.character(cyl))) +
    geom_bar(stat = "identity", fill = NA, color = "black")
  print(static_plot) # see that here we have different linetypes as expected
  
  ggplotly(static_plot) # the lines are all the same i.e continuous!
  </code></pre>
  
  <p><strong>output from <code>print(static_plot)</code> with expected linetypes:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/kCHCdl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/kCHCdl.png" alt="output from print() with expected linetypes"></a></p>
  
  <p><strong>ouput from <code>ggplotly(static_plot)</code>; linetype aesthetic has not been taken into account</strong></p>
  
  <p><a href="https://i.stack.imgur.com/yT3QKl.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yT3QKl.jpg" alt="ouput from &lt;code&gt;ggplotly()&lt;/code&gt;"></a></p>
  
  <pre><code># using a geom_line it works fine
  static_plot2 = ggplot(data = mtcars, aes(x = disp, y = mpg, linetype=as.character(cyl))) +
    geom_line(color = "black")
  print(static_plot2)
  
  ggplotly(static_plot2)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/qxrgIm.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qxrgIm.jpg" alt="working example with geom_line"></a></p>
  
  <p>Maybe this is obvious but I can't find the trick to do it...</p>