fix: hide billing plan container when name is empty or null

lib/features/profile/presentation/widgets/billing_tab.dart

@@ -144,6 +144,7 @@ class _BillingTabState extends ConsumerState<BillingTab>
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
+          if ((plan?['name'] as String?)?.trim().isNotEmpty == true) ...[
             Container(
               padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 10),
               decoration: BoxDecoration(
@@ -151,7 +152,7 @@ class _BillingTabState extends ConsumerState<BillingTab>
                 borderRadius: BorderRadius.circular(15),
               ),
               child: Text(
-              plan?['name'] as String? ?? 'Annual Subscription',
+                plan!['name'] as String,
                 style: const TextStyle(
                   fontFamily: 'SourceSerif4',
                   fontSize: 14,
@@ -160,6 +161,7 @@ class _BillingTabState extends ConsumerState<BillingTab>
               ),
             ),
             const SizedBox(height: 20),
+          ],
           Row(
             children: [
               const Icon(Icons.check_circle,