By Pawel Florkiewicz, Michael Kahn and Riham Alkousaa WARSAW/PRAGUE/BERLIN (Reuters) – Ukrainian refugees filled churches across central Europe on Sunday for Orthodox Easter in bittersweet celebrations, giving thanks for escaping a Russian invasion but dreaming of a return home to family members left behind. At Warsaw’s Orthodox Cathedral of St. Mary Magdalene in the city centre where priests said holiday services were busier than in past years, children carried Easter baskets adorned with Ukrainian flags and had blue and yellow bows in their hair. “This is my first Easter holiday that I am no…