UX: Upgrade to fontawesome 6.6.0 (#28778)

This upgrade is designed to be fully backwards-compatible. Any icon names which have changed will be automatically remapped to the new name. For now, this will happen silently. In future, once core & official themes/plugins have been updated, we will start raising deprecation errors to help theme/plugin authors update their code.

Extracted from https://github.com/discourse/discourse/pull/28715

Announcement at https://meta.discourse.org/t/were-upgrading-our-icons-to-font-awesome-6/325349

Co-authored-by: awesomerobot <kris.aubuchon@discourse.org>

plugins/discourse-local-dates/assets/javascripts/initializers/discourse-local-dates.js

@@ -41,7 +41,7 @@ export function applyLocalDates(dates, siteSettings) {
     element.innerText = "";
     element.insertAdjacentHTML(
       "beforeend",
-      `${iconHTML("globe-americas")}
+      `${iconHTML("earth-americas")}
         <span class="relative-time">${localDateBuilder.formatted}</span>`
     );
     element.setAttribute("aria-label", localDateBuilder.textPreview);