I don't think very many Kurdish Proverbs were proverbially in English. So, I doubt that "Parting is such sweet sorrow" was ever a Kurdish proverb (though some similar sentiment in Kurdish may be a Kurdish proverb, for all I know).

Shakespeare did not know Kurdish. He was very unlikely to have any sources for Kurdish proverbs. I think we can say, with a great deal of certainty, that Shakespeare created this line, and that it owed nothing to Kurdish proverbs.