DEFAULT_MODEL not working for Azure

[progmancod]

The environment variable DEFAULT_MODEL doesn't work with OPENAI_API_TYPE=azure because Object.values(OpenAIModelID).includes(
process.env.DEFAULT_MODEL as OpenAIModelID,
) in home.tsx always returns false, falling back on fallbackModelID.

[makeneko]

I am using Azure OpenAI and the DEFAULT_MODEL environment variable is working.
When using Azure OpenAI, the default values cannot be used because the model names are different.

https://learn.microsoft.com/en-us/azure/ai-services/openai/concepts/models#gpt-4-models