Fix admin user list being empty

After 4ff3dcb the admin user list became empty due to a messing fetch of
the userStore on the admin page.

pages/admin.vue

@@ -101,6 +101,9 @@ useHead({
 	title: "Admin",
 });
 
+const usersStore = useUsersStore();
+await usersStore.fetch();
+
 const tabs = [
 	{ id: "users", title: "Users" },
 	{ id: "database", title: "Database" },