ROME (Reuters) – Italy’s centrist Azione party will leave a centre-left election alliance it formed with the Democratic Party (PD) earlier this week ahead of a Sept. 25 ballot, Azione’s party leader said on Sunday. Azione’s decision to withdraw comes a day after the Italian Green leftist federation and centrist party Impegno Civico, agreed to join the PD-led alliance, a move that was seen as strengthening the centre-left which is already lagging behind conservative rivals. Polls show that a conservative alliance is set to win next month’s election, with far-right the Brothers of Italy set to b…