fix: pylint issue

Author: Prashant-Microsoft

src/backend/kernel_agents/group_chat_manager.py

@@ -380,7 +380,7 @@ async def _execute_step(self, session_id: str, step: Step):
 
         if step.agent != "":
             agent_name = step.agent.value
-            formatted_agent = agent_name.replace("_"," ")
+            formatted_agent = agent_name.replace("_", " ")
         else:
             raise ValueError(f"Check {step.agent} is missing")