Copilot Free users with exhausted Chat requests can no longer use BYOK

[pierceboggan]

https://www.reddit.com/r/GithubCopilot/comments/1lfh53k/are_other_models_that_use_my_own_openai_api_keys/?utm_source=ifttt

Once Copilot Free has no more chat requests remaining, even if the user moves to a BYOK model we try to auto-switch them back to GPT 4.1.