Add xAI's Grok Code Fast 1 model (#36959)

Release Notes:

- Add the `grok-code-fast-1` model to xAI's list of available models.
d7c735959eDaniel Dye committed on 8/26/2025, 9:08:45 PM· committed by GitHubparentd884719
2 files changedLine totals unavailable