Add possibility to set random seed for smoothed p-values

[egonmedhatten]

Hi,

In order to ensure repdoducability of experiments, it would be useful to be able to set a random seed for the computation of smoothed p-values. In particular when working with small datasets. One solution might be to pass the seed as an optional argument to WrapClassifyer/WrapRegressor.

[tuvelofstrom]

I would like to second this request. I have an issue requesting this functionality in calibrated-explanations, where we get different explanations for the same instance depending on whether we make a batch explanation of multiple instances or explain one instance at a time.