adding missing const

frontend/lib/modules/onboarding_card.dart

@@ -6,7 +6,7 @@ class OnboardingCard extends StatelessWidget {
   final String description;
   final String imagePath;
 
-  const OnboardingCard({
+  const OnboardingCard({super.key,
     required this.title,
     required this.description,
     required this.imagePath,
@@ -14,9 +14,9 @@ class OnboardingCard extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    
+
     return Padding(
-      padding: EdgeInsets.all(20),
+      padding: const EdgeInsets.all(20),
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: [
@@ -26,12 +26,12 @@ class OnboardingCard extends StatelessWidget {
               color: Colors.white,
             ),
           ),
-          Padding(padding: EdgeInsets.only(top: 20)),
+          const Padding(padding: EdgeInsets.only(top: 20)),
           SvgPicture.asset(
             imagePath,
             height: 200,
           ),
-          Padding(padding: EdgeInsets.only(top: 20)),
+          const Padding(padding: EdgeInsets.only(top: 20)),
           Text(
             description,
             style: Theme.of(context).textTheme.bodyMedium!.copyWith(