fix: Ensure agent id is unique in RandomActivationByType.add

Author: rht

mesa/time.py

@@ -236,7 +236,7 @@ def add(self, agent: Agent) -> None:
             agent: An Agent to be added to the schedule.
         """
 
-        self._agents[agent.unique_id] = agent
+        super().add(agent)
         agent_class: Type[Agent] = type(agent)
         self.agents_by_type[agent_class][agent.unique_id] = agent