ASE: Set calculator to structure before initializing the Executor

[jan-janssen]

This caused the calculator in the Molecular Dynamics calcualtion to be overwritten.

[liamhuber]

This caused the calculator in the Molecular Dynamics calcualtion to be overwritten.

I'm not sure I'm familiar enough with ASE and how its structure and calculator objects interact, so take this with a big grain of salt, but this smells dangerous to me.

I would expect there to be some guarantee that the calculator at evaluation time is the same calculator I defined at the beginning of the run... Is this a faulty assumption? The direction I'm thinking is to still take the calculator in the output object, but instead of applying it ot the structure's .calc attribute just self.structure.calculator is not ase_calculator: raise ValueError(...) or similar.