[COG-948] Fix ContextWindowExceededError in CodeGraph

[lxobr]

instructor.exceptions.InstructorRetryException: 
litellm.BadRequestError: 
litellm.ContextWindowExceededError: 
ContextWindowExceededError: 
OpenAIException - Error code: 400  
{
  'error': 
    {
      'message': "This model's maximum context length is 128000 tokens. However, your messages resulted in 150820 tokens (150655 in the messages, 165 in the functions). Please reduce the length of the messages or functions.", 
      'type': 'invalid_request_error', 
      'param': 'messages', 
      'code': 'context_length_exceeded'
    }
}

• A check should be implemented for the length of request message that we are sending.
• We can use tiktoken to count the tokens.
• Large requests should be chunked into smaller requests.

_{From SyncLinear.com | COG-948}