AiiDAEnsemble: add missing self.init()

Fixes #334

The version update v1.4.1 missed to add the new `init` function to the
`compute_ensemble` method of the auxiliary class `AiiDAEnsemble`.
The simple fix makes the calculation using this class comparable to
the traditional `Ensemble` class.

Author: bastonero

Modules/aiida_ensemble.py

@@ -100,6 +100,7 @@ def compute_ensemble(
             self.stress_computed = copy(self.force_computed)
 
         self._clean_runs()
+        self.init()
 
     def _clean_runs(self) -> None:
         """Clean the failed runs and print summary."""