fix(app): default impl for strong box

Author: Numoy

flutter_secure_storage_platform_interface/lib/flutter_secure_storage_platform_interface.dart

@@ -126,5 +126,7 @@ abstract class FlutterSecureStoragePlatform extends PlatformInterface {
   /// 
   /// Returns:
   /// - A [Future] that resolves to `true` if the device supports secure hardware-backed storage, or `false` otherwise.
-  Future<bool> isStrongBoxSupported();
+  Future<bool> isStrongBoxSupported() {
+    throw UnsupportedError('isStrongBoxSupported() is not available on this platform');
+  }
 }

flutter_secure_storage_windows/lib/src/flutter_secure_storage_windows_ffi.dart

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