Update link in event themes page to correct path

Fixed the href value in the "Create Your First Theme" button to point to the correct `/dashboard/event-themes/new` route. This ensures proper navigation and resolves potential routing issues.

frontend/src/app/(main)/dashboard/event-themes/page.tsx

@@ -52,7 +52,9 @@ export default function EventThemesPage() {
             You haven't created any theme yet.
           </p>
           <Button asChild className="mt-4">
-            <Link href="/dashboard/events/new">Create Your First Theme</Link>
+            <Link href="/dashboard/event-themes/new">
+              Create Your First Theme
+            </Link>
           </Button>
         </div>
       )}