Motivation: we have users who uses their API key although they want to use ChatGPT account. We want to give them the chance to always login with their account. This PR displays login options when the user is not signed in with ChatGPT. Even if you have set an OpenAI API key as an environment variable, you will still be prompted to log in with ChatGPT. We’ve also added a new flag, `always_use_api_key_signing` false by default, which ensures you are never asked to log in with ChatGPT and always defaults to using your API key. https://github.com/user-attachments/assets/b61ebfa9-3c5e-4ab7-bf94-395c23a0e0af After ChatGPT sign in: https://github.com/user-attachments/assets/d58b366b-c46a-428f-a22f-2ac230f991c0