By Michael Holden LONDON (Reuters) – The five Conservative contenders still vying to be Britain’s next prime minister will clash in a second televised debate on Sunday when they are set to renew hostilities over tax policy and issues such as transgender rights. With no clear candidate to succeed Boris Johnson who is stepping down after a series of scandals, the battle to be the next leader remains unpredictable and increasingly fractious, exposing rifts in the ruling Conservative Party. Ex-finance minister Rishi Sunak has emerged as the favourite among the 358 Conservative lawmakers, who will …