fix arch_config schema

demos/samples_python/human_resources_agent/arch_config.yaml

@@ -9,10 +9,8 @@ listeners:
 
 # Centralized way to manage LLMs, manage keys, retry logic, failover and limits in a central way
 llm_providers:
-  - name: OpenAI
-    provider_interface: openai
-    access_key: $OPENAI_API_KEY
-    model: gpt-4o-mini
+  - access_key: $OPENAI_API_KEY
+    model: openai/gpt-4o-mini
     default: true
 
 # Arch creates a round-robin load balancing between different endpoints, managed via the cluster subsystem.