 Fix check for callbacks (#2251)
 Fix check for callbacks (#2251)

Use `any()` method to check if there are any metric in `self.metrics` is a instance of `(DiffMetric, ConvergenceMetric)`
piskvorky/gensim,RaRe-Technologies/gensim,gojomo/gensim,gojomo/gensim,RaRe-Technologies/gensim,gojomo/gensim,piskvorky/gensim,RaRe-Technologies/gensim,RaRe-Technologies/gensim,gojomo/gensim,piskvorky/gensim