Remove need to set server chat settings from use openai proxies docs

This was previously required, but now it's only usefuly for more
advanced settings, not typical for self-hosting users.

With recent updates, the user's selected chat model is used for both
Khoj's train of thought and response. This makes it easy to
switch your preferred chat model directly from the user settings
page and not have to update this in the admin panel as well.

Reflect these code changse in the docs, by removing the unnecessary
step for self-hosted users to create a server chat setting when using
an OpenAI proxy service like Ollama, LiteLLM etc.

documentation/docs/advanced/use-openai-proxy.md

@@ -31,7 +31,4 @@ For specific integrations, see our [Ollama](/advanced/ollama), [LMStudio](/advan
    - Openai Config: `<the proxy config you created in step 2>`
    - Max prompt size: `2000` (replace with the max prompt size of your model)
    - Tokenizer: *Do not set for OpenAI, mistral, llama3 based models*
-4. Create a new [Server Chat Setting](http://localhost:42110/server/admin/database/serverchatsettings/add/) on your Khoj admin panel
-   - Default model: `<name of chat model option you created in step 3>`
-   - Summarizer model: `<name of chat model option you created in step 3>`
-5. Go to [your config](http://localhost:42110/settings) and select the model you just created in the chat model dropdown.
+4. Go to [your config](http://localhost:42110/settings) and select the model you just created in the chat model dropdown.