fix(app): emtpy impl strongbox windows

Author: Numoy

flutter_secure_storage_windows/lib/src/flutter_secure_storage_windows_ffi.dart

@@ -178,6 +178,13 @@ class FlutterSecureStorageWindows extends FlutterSecureStoragePlatform {
       await _backwardCompatible.delete(key: key, options: options);
     }
   }
+
+  @override
+  Future<bool> isStrongBoxSupported() async {
+    throw UnsupportedError(
+      'isStrongBoxSupported() is not available on this platform',
+    );
+  }
 }
 
 /// Creates a custom instance of `FlutterSecureStorageWindows` for testing.

flutter_secure_storage_windows/lib/src/flutter_secure_storage_windows_stub.dart

@@ -49,6 +49,13 @@ class FlutterSecureStorageWindows extends FlutterSecureStoragePlatform {
   }) =>
       Future.value();
 
+  @override
+  Future<bool> isStrongBoxSupported() async {
+    throw UnsupportedError(
+      'isStrongBoxSupported() is not available on this platform',
+    );
+  }
+
   // @override
   // Future<bool> isCupertinoProtectedDataAvailable() => Future.value(true);
   //