language_models: Fix `grok-code-fast-1` support for Copilot (#37116)

This PR fixes a deserialization issue in GitHub Copilot Chat that was
causing warnings when encountering xAI models from the GitHub Copilot
API and skipping the Grok model from model selector.

Release Notes:

- Fixed support for xAI models that are now available through GitHub
Copilot Chat.
c833f8905bUmesh Yadav committed on 8/31/2025, 10:51:17 PM· committed by GitHubparentd74384f
2 files changedLine totals unavailable