feat: New notification panel for unread notifications (#4061)

Fixes: #4052

app/javascript/dashboard/components/layout/Sidebar.vue

@@ -8,6 +8,7 @@
       :active-menu-item="activePrimaryMenu.key"
       @toggle-accounts="toggleAccountModal"
       @key-shortcut-modal="toggleKeyShortcutModal"
+      @open-notification-panel="openNotificationPanel"
     />
     <secondary-sidebar
       :account-id="accountId"
@@ -176,6 +177,9 @@ export default {
     showAddLabelPopup() {
       this.$emit('show-add-label-popup');
     },
+    openNotificationPanel() {
+      this.$emit('open-notification-panel');
+    },
   },
 };
 </script>