Add GPT-5.4 to inference OpenAIModels type

Add the model to the OpenAIModels type so it's available
via LiveKit inference.

Author: Topherhindman

agents/src/inference/llm.ts

@@ -17,6 +17,7 @@ import { type AnyString, createAccessToken } from './utils.js';
 const DEFAULT_BASE_URL = 'https://agent-gateway.livekit.cloud/v1';
 
 export type OpenAIModels =
+  | 'openai/gpt-5.4'
   | 'openai/gpt-5.2'
   | 'openai/gpt-5.2-chat-latest'
   | 'openai/gpt-5.1'