chore: update the openai model to use the latest version

Author: kartik-mem0

yaml_instance/demo_mem0_memory.yaml

@@ -11,7 +11,7 @@ graph:
         base_url: ${BASE_URL}
         api_key: ${API_KEY}
         provider: openai
-        name: gpt-4o
+        name: gpt-5.4
         role: |
           You are a knowledgeable writer. Use your memories to build on past interactions.
           If memory sections are provided (wrapped by ===== Related Memories =====),