R15 fix elo (#5151)

* add group done to ELO computation

* add not interrupted

ml-agents/mlagents/trainers/ghost/trainer.py

         i.e. in asymmetric games. We assume the last reward determines the winner.
         :param trajectory: Trajectory.
         """
-        if trajectory.done_reached:
+        if (
+            trajectory.done_reached
+            and trajectory.all_group_dones_reached
+            and not trajectory.interrupted
+        ):
             # Assumption is that final reward is >0/0/<0 for win/draw/loss
             final_reward = (
                 trajectory.steps[-1].reward + trajectory.steps[-1].group_reward