Prevent aria-hidden button receiving focus (#15137) (#15320)

bedrock/firefox/templates/firefox/challenge-the-default/includes/wednesday.html

@@ -13,7 +13,7 @@
       <circle class="wednesday-circle light-green circle3" cx="719.996" cy="123" r="372" fill="#D1FFEE" />
       <circle cx="719.996" cy="123" r="283" fill="#2AC3A2" />
     </svg>
-    <button class="animated-button ctd-logo-sprite">Challenge the default</button>
+    <button class="animated-button ctd-logo-sprite" tabindex="-1">Challenge the default</button>
     {{ resp_img(
         url='img/firefox/challenge-the-default/is-wednesday.png',
         optional_attributes={