By Alvaro Murillo SAN JOSE (Reuters) -Costa Ricans on Sunday began casting ballots in an election with a record 25 candidates vying to succeed outgoing President Carlos Alvarado, but the voting is unlikely to produce an outright winner and a second-round is scheduled for April. No candidate, including former President Jose Maria Figueres, is expected to win more than 40% of votes, the threshold to avoid a runoff between the two top vote-getters, according to a poll published on Tuesday by the University of Costa Rica’s Center for Research and Political Studies. All 57 seats of the unicameral l…