Client not deleting SQS messages

[reese-allison]

Currently, the delete_messages function fails to delete the message in SQS because it is unable to get the correct original receipt handle. It's a simple fix.

def _get_original_receipt_handle(self, modified_receipt_handle: str) -> str:
    """
    Responsible for returning the receipt handle of the message before 
    it was modified.

    :modified_receipt_handle: Represents the receipt handle which was modified
    when the message was stored in S3.

    """
    return modified_receipt_handle.split(S3_KEY_MARKER)[-1]