decryptFileFromPath method
Decrypts an encrypted file into the corresponding clear-text file.
encryptedFilePath - The path of the encrypted file to decrypt.
Returns the path of the decrypted file.
Implementation
String decryptFileFromPath(String encryptedFilePath) {
  final Pointer<Utf8> nativeEncryptedFilePath =
      encryptedFilePath.toNativeUtf8();
  final Pointer<Pointer<Utf8>> result = calloc<Pointer<Utf8>>();
  final Pointer<Pointer<NativeSealdError>> err =
      calloc<Pointer<NativeSealdError>>();
  final int resultCode =
      _bindings.SealdAnonymousEncryptionSession_DecryptFileFromPath(
          _ptr.pointer(), nativeEncryptedFilePath, result, err);
  calloc.free(nativeEncryptedFilePath);
  if (resultCode != 0) {
    calloc.free(result);
    throw SealdException._fromCPtr(err);
  } else {
    final String decryptedFilePath = result.value.toDartString();
    calloc.free(result.value);
    calloc.free(result);
    calloc.free(err);
    return decryptedFilePath;
  }
}