By Emilio Parodi MILAN (Reuters) -An Italian appeals court on Monday acquitted three former top executives of Banca Monte dei Paschi di Siena in one strand of a long-running derivatives case, boosting the earnings prospects of the state-owned lender. The court ruling, which overturns an earlier conviction, reduces the legal risks facing bailed-out Monte dei Paschi (MPS), in which the state still has a 39% holding after selling a 25% stake last month for 920 million euros ($989 million). The Italian state must eventually exit MPS’s capital in full in order to comply with European Union rules on…