Rename v5 FontAwesome icons to match v6 name

While FontAwesome provides aliases for all icons, we switch to the new names for consistency. See all changes at:
https://fontawesome.com/docs/web/setup/upgrade/whats-changed#icons-renamed-in-version-6

app/views/community_solutions/_form.html.slim

@@ -10,7 +10,7 @@
   #description-card.lead class=(@embed_options[:collapse_exercise_description] ? 'description-card-collapsed' : 'description-card')
     .card.border-success.mb-3
       .card-header
-        i.fa.fa-info-circle.text-success
+        i.fa.fa-circle-info.text-success
         strong.text-success
           => t('community_solutions.help_us_out')
         = t('community_solutions.explanation')