Real estate mogul Rotem Rosen is on a roll. The ex-son-in-law of post-Soviet billionaire Tamir Sapir has filed plans to build a 346-foot-tall, 180,000-square-foot condo tower with 145 units at 126 E. 57th St., Crain’s reported. Rosen’s MRR Capital — which he owns with Indian billionaire Anand Mahindra — and partner Tzachi Hagag, an Israeli developer,...