Implement geom_bar_pattern in plotly? 

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The use of geom_bar_pattern appears to be incompatible with plotly. The below graph will print in standard format but fail to print with ggplotly. 

```r
plot <- ggplot(mtcars, aes(x=factor(cyl), y=mpg))+
  geom_bar_pattern(aes(y=mpg, pattern=factor(vs)), stat="summary", width=0.5, position=position_dodge(0.7))
   
print(plot)
plotly::ggplotly(plot)
```
