Remove domain helper and fix typos

src/common/util/domain.ts

-export function getDomainName(hostName: string) {
-  return hostName.substring(hostName.lastIndexOf('.', hostName.lastIndexOf('.') - 1) + 1);
-}

src/components/Header/Header.tsx

@@ -42,7 +42,7 @@ const Header: React.FC<HeaderProps> = () => {
 
   const navigationItems = filterNavigationByDashboardRole(isAdmin);
 
-  const singOutUrl = `${HYDRA_URL}/oauth2/sessions/logout`;
+  const signOutUrl = `${HYDRA_URL}/oauth2/sessions/logout`;
 
   return (
     <>
@@ -124,7 +124,7 @@ const Header: React.FC<HeaderProps> = () => {
                           {({ active }) => (
                             <a
                               onClick={() => logOut()}
-                              href={singOutUrl}
+                              href={signOutUrl}
                               className={classNames(
                                 active ? 'bg-gray-100 cursor-pointer' : '',
                                 'block px-4 py-2 text-sm text-gray-700 cursor-pointer',