Bug 1917563 - fix focus in sidebar history when history data is pending r=sidebar-reviewers,nsharpley

Differential Revision: https://phabricator.services.mozilla.com/D221530

browser/components/sidebar/sidebar-history.mjs

@@ -93,7 +93,10 @@ export class SidebarHistory extends SidebarPage {
    * The template to use for cards-container.
    */
   get cardsTemplate() {
-    if (this.controller.searchResults) {
+    if (this.controller.isHistoryPending) {
+      // don't render cards until initial history visits entries are available
+      return "";
+    } else if (this.controller.searchResults) {
       return this.#searchResultsTemplate();
     } else if (!this.controller.isHistoryEmpty) {
       return this.#historyCardsTemplate();
@@ -230,11 +233,6 @@ export class SidebarHistory extends SidebarPage {
     this._menu.openPopup(e.target, menuPos, 0, 0, false, false, e);
   }
 
-  shouldUpdate() {
-    // don't update/render until initial history visits entries are available
-    return !this.controller.isHistoryPending;
-  }
-
   willUpdate() {
     this._menuSortByDate.setAttribute(
       "checked",