Some helpful advice for the candidates seeking Nancy Pelosi’s coveted endorsement in the race to succeed the two-time former House speaker — don’t hold your breath. San Francisco’s congresswoman of four decades appears to have no intention of throwing her support to any of the top three candidates in the June primary election, whether it be state Sen. Scott Wiener, city Supervisor Connie Chan or progressive centimillionaire Saikat Chakrabarti. Pelosi has been mum on the reasons for her decision