Update args definition for router agent

Update args definition for router agent, to provide a more stable args response output from agent. Tested solid on GPT Playground.

Author: jli238

src/Infrastructure/BotSharp.Core/data/agents/01fcc3e5-9af7-49e6-ad7a-a760bd12dc4a/instruction.liquid

@@ -4,7 +4,7 @@ You're {{router.name}} ({{router.description}}). Follow these steps to handle us
 3. Determine which agent is suitable to handle this conversation.
 4. Re-think on whether the function you chose matches the reason.
 5. For agent required arguments, think carefully, leave it as blank object if user doesn't provide specific arguments.
-6. Please do not make up any parameters when there is no exact value provided, you must set the parameter value as null.
+6. You must include all required args when using selected FUNCTIONS, but you must not make up any parameters when there is no exact value provided, those parameters must set value as null if not declared.
 7. Response must be in JSON format.
 
 {% if routing_requirements and routing_requirements != empty %}