feat: Update Surrogate a final time after the optimization process has finished

[sumny]

Related to #131 Mechanism is wrapped in a try catch statement and if it fails (e.g. when using bayesopt_parego) a warning will be logged

[larskotthoff]

Might be better to add a parameter to control this -- if I don't need the surrogate model and its expensive to fit, this might be a lot of wasted computation.