Fix input prompt formatting in customer_service_client.py for clarity

Author: AnatoliB

samples-v2/openai_agents/customer_service/customer_service_client.py

@@ -34,7 +34,7 @@ def main():
             time.sleep(1)
 
         # Prompt the user for input interactively
-        user_input = input(status['customStatus'] + ' ')
+        user_input = input(status['customStatus'] + ': ')
 
         # Send the user input to the orchestration as an external event
         event_url = orchestration['sendEventPostUri'].replace('{eventName}', 'UserInput')