Update logic to hide empty cta span

Author: huguestennier

src/site/_includes/banner.njk

@@ -1,3 +1,3 @@
 <a href="{{ announcementbar.url }}" class="block p-2 md:py-2 text-center text-white font-bold text-xs md:text-sm bg-gradient-jams bg-gradient-pink-orange group">
-  {{ announcementbar.text }} <span class="underline group-hover:no-underline">{{ announcementbar.cta }}</span>
+  {{ announcementbar.text }} {% if announcementbar.cta %}<span class="underline group-hover:no-underline">{{ announcementbar.cta }}</span>{% endif %}
 </a>