file-mode-api: remove unnecessary check

Author: aldogonzalez8

airbyte_cdk/sources/file_based/file_based_stream_reader.py

@@ -186,9 +186,6 @@ def _get_file_transfer_paths(
             - FILE_NAME: The name of the referenced file.
             - FILE_FOLDER: The folder of the referenced file.
         """
-        if not path.exists(staging_directory):
-            raise ValueError(f"Staging directory '{staging_directory}' does not exist")
-
         preserve_directory_structure = self.preserve_directory_structure()
 
         file_name = path.basename(source_file_relative_path)