Ggpattern integration.

When working with `ggplot2` I would like to render a textured filling with `ggpattern` and more particularly with `ggpattern::geom_polygon_pattern()`.

```r
library(ggplot2)
library(ggpattern)
library(plotly)
g <- ggplot(mtcars) +geom_boxplot_pattern(aes(x=mpg))
ggplotly(g)
```
