Add missing white background to icon
Add missing white background to icon

This icon was named white-background, but it was transparent since that
is what the original SVG is. Add a background option to fix this so it
looks good on iOS and doesn't get the ugly black default background.

ilios/frontend,dartajax/frontend,thecoolestguy/frontend,ilios/frontend,dartajax/frontend,jrjohnson/frontend,jrjohnson/frontend,thecoolestguy/frontend