Validation: Fix conversation.id format

[sentry]

Describe the bug you are facing
We are encountering a BadRequestError due to an invalid conversation.id format. This issue prevents proper API calls, leading to workflow interruptions.
Sentry Issue: KAAPI-PRODUCTION-B

BadRequestError: Error code: 400 - {'error': {'message': "Invalid 'conversation.id': '@results.llm_thread_id.input'. Expected an ID that contains letters, numbers, underscores, or dashes, but this value contained additional characters.", 'type': 'invalid_request_error', 'param': 'conversation.id', 'code': 'invalid_value'}}
  File "openai/resources/responses/responses.py", line 898, in create
    return self._post(
  File "openai/_base_client.py", line 1297, in post
    return cast(ResponseT, self.request(cast_to, opts, stream=stream, stream_cls=stream_cls))
  File "openai/_base_client.py", line 1070, in request
    raise self._make_status_error_from_response(err.response) from None

Describe the solution you'd like

• Validate the conversation.id to ensure it follows OpenAI conventions before making an API call to OpenAI
• Provide a meaningful error message and status code so this can be handled gracefully by a platform like Glific in their flows

[AkhileshNegi]

we have raised this issue with Glific team, since this is user side error, Glific team will plan next steps and may reach out to NGOs and help them fix flows
Discord thread: https://discord.com/channels/717975833226248303/1513875842814705736