[brief] Allow the Optuna plugin to stop if the trial number exceeds t…

…he count

[detailed]
- Mainly to allow the case where the number of trials has already
  exceeded the total count.

src/helios/plugins/optuna.py

@@ -215,7 +215,7 @@ def setup(self) -> None:
                 "in distributed mode"
             )
 
-        if self._num_trials is not None and self.trial.number == (self._num_trials - 1):
+        if self._num_trials is not None and self.trial.number >= (self._num_trials - 1):
             self.trial.study.stop()
 
     def on_validation_end(self, validation_cycle: int) -> None: