remove throw UnimplementedError(#aes-algorithm)

Author: LamNguyen176

lib/flutter_crypto_algorithm_platform_interface.dart

@@ -23,11 +23,7 @@ abstract class FlutterCryptoAlgorithmPlatform extends PlatformInterface {
     _instance = instance;
   }
 
-  Future<String?> encrypt(String value, String privateKey, String? ivKey) {
-    throw UnimplementedError('encrypt(value, privateKey, ivKey?) has not been implemented.');
-  }
+  Future<String?> encrypt(String value, String privateKey, String? ivKey);
 
-  Future<String?> decrypt(String value, String privateKey, String? ivKey) {
-    throw UnimplementedError('decrypt(value, privateKey, ivKey?) has not been implemented.');
-  }
+  Future<String?> decrypt(String value, String privateKey, String? ivKey);
 }