`threads/start` doesn't throw a clear validation error

[Ishankoradia]

Describe the bug
When the payload uses query instead of question, the api /threads/start throws a generic 500 exception which is very confusing for the client.

To Reproduce
Steps to reproduce the behavior:

1. Hit the threads api with a different payload key. For eg. query instead of question

Expected behavior
Should throw a client 4xx error with proper message saying the required key is not present in the payload

Screenshots

Additional context