style: fix page to use function instead of const to be consistent

frontend/src/app/mottakskontroll/dine-saker/dashbord/[caseNumber]/page.tsx

@@ -3,14 +3,12 @@
 import { useParams } from "next/navigation";
 import React from "react";
 
-const CaseDashboard: React.FC = () => {
+export default function CaseDashboard() {
   const { caseNumber } = useParams();
 
   return (
     <div>
       <h1>Dashbord for saksnummer: {caseNumber}</h1>
     </div>
   );
-};
-
-export default CaseDashboard;
+}