Changes to Retrieve a transcription

added the pattern ^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$ to the path request parameter call_id

for the path request parameter call_id, the format changed from no format to uuid

added the non-success response with the status 401

endpoint added