Fix map icons (#2712)

Some material icons were being wrongly detected as font-awesome ones
e.g. "fastfood"

Reviewed-on: https://codeberg.org/karrot/karrot-frontend/pulls/2712
Co-authored-by: Nick Sellen <git@nicksellen.co.uk>
Co-committed-by: Nick Sellen <git@nicksellen.co.uk>

src/maps/components/vectorIcon.js

@@ -16,7 +16,7 @@ const VectorIcon = Icon.extend({
 
     if (fontIcon) {
       const i = document.createElement('i')
-      if (fontIcon.includes('fa')) {
+      if (/^fa.? /.test(fontIcon)) {
         // Font-awesome icon
         // Uses class names
         i.className = `${fontIcon} fa-fw`