Bug 1861527 - On change of category, scroll to the top of the page r=fxview-reviewers,kcochrane

- added `window.scrollTo(0, 0)` to `change-category` event listener callback

Differential Revision: https://phabricator.services.mozilla.com/D193969

browser/components/firefoxview/firefoxview-next.mjs

@@ -54,6 +54,7 @@ window.addEventListener("DOMContentLoaded", async () => {
   window.addEventListener("hashchange", onHashChange);
   window.addEventListener("change-category", function (event) {
     location.hash = event.target.getAttribute("name");
+    window.scrollTo(0, 0);
     recordNavigationTelemetry("category-navigation", event.target);
   });
   window.addEventListener("card-container-view-all", function (event) {