Fix passing temp kwarg to non-streaming openai completion endpoint

It is already being passed in model_kwargs, so not required to be
passed explicitly as well.

This code path isn't being used currently, but better to fix for
if/when it is used

src/khoj/processor/conversation/openai/utils.py

@@ -195,7 +195,6 @@ def completion_with_backoff(
         chunk = client.beta.chat.completions.parse(
             messages=formatted_messages,  # type: ignore
             model=model_name,
-            temperature=temperature,
             timeout=httpx.Timeout(30, read=read_timeout),
             **model_kwargs,
         )