Russian prosecutors requested a 15-year prison sentence for a dual U.S.-Russian citizen accused of donating money to a Ukrainian charity, state media reported Thursday, citing her lawyer. Ksenia Karelina was arrested in January while visiting her family in the Ural Mountains city of Yekaterinburg. On Wednesday, she pleaded guilty to treason charges during a closed hearing, her lawyer Mikhail Mushailov said. “The prosecution requested a sentence of 15 years imprisonment,” Mushailov told state media on Thursday, adding that a judge would announce a final verdict on Aug. 15. Treason cases are hea…