Styles are duplicated

[andreyfel]

I was trying to use this addon in my addon with the new feature of specifying icons required by the addon.
When I launch the dummy app I see that fontawesome styles (.svg-inline--fa and others) are inserted directly to the html within the style tag and also included in the vendor.css.

[andreyfel]

I've just tried on the regular app and it has the same issue: styles are duplicated in style tag and vendor.css.