Fix RobotRumble

Author: john-b-yang

codeclash/games/robotrumble/robotrumble.py

@@ -42,11 +42,12 @@ def _run_single_simulation(self, agents: list[Player], idx: int, cmd: str):
             response = self.environment.execute(cmd, timeout=120)
         except subprocess.TimeoutExpired:
             self.logger.warning(f"RobotRumble simulation {idx} timed out: {cmd}")
-            return
+            return ""
         if response["returncode"] != 0:
             self.logger.warning(
                 f"RobotRumble simulation {idx} failed with exit code {response['returncode']}:\n{response['output']}"
             )
+        return response["output"]
 
     def execute_round(self, agents: list[Player]):
         self.logger.info(f"Running game with players: {[agent.name for agent in agents]}")