Updated: failed key to nullable

Author: we-mohd-i001

lib/vaahextendflutter/services/storage/local/services/flutter_secure_storage.dart

@@ -362,7 +362,6 @@ class LocalStorageWithFlutterSecureStorage implements LocalStorageService {
       errors: [
         StorageError(
           message: 'No keys provided',
-          failedKey: '',
           stackTrace: StackTrace.current,
         ),
       ],
@@ -381,7 +380,6 @@ class LocalStorageWithFlutterSecureStorage implements LocalStorageService {
       return StorageResponse(errors: [
         StorageError(
           message: 'Delete failed: ${e.toString()}',
-          failedKey: '',
           stackTrace: StackTrace.current,
         )
       ]);

lib/vaahextendflutter/services/storage/storage_error.dart

@@ -1,8 +1,12 @@
 class StorageError {
   final String message;
-  final String failedKey;
+  final String? failedKey;
   final StackTrace stackTrace;
-  StorageError({required this.message, required this.failedKey, required this.stackTrace});
+  StorageError({
+    required this.message,
+    this.failedKey,
+    required this.stackTrace,
+  });
 
   @override
   String toString() =>