Rename the gpt-4-turbo aliases

[simonw]

Currently:

llm/llm/default_plugins/openai_models.py

Lines 30 to 33 in ab1cc4f

	# GPT-4 turbo models
	register(Chat("gpt-4-1106-preview"))
	register(Chat("gpt-4-0125-preview"))
	register(Chat("gpt-4-turbo-preview"), aliases=("gpt-4-turbo", "4-turbo", "4t"))

But quite recently OpenAI made gpt-4-turbo a valid reference to the latest GPT-4 Turbo (including vision) API model.

[simonw]

I'm just going to swap gpt-4-turbo-preview to be an alias, not a model name.

This does mean people with existing log databases will have old gpt-4-turbo-preview records and new gpt-4-turbo records but I think that's OK, I'll mention that in the release notes.