By Elizabeth Piper and Andrew MacAskill LONDON (Reuters) -British Prime Minister Boris Johnson survived a confidence vote on Monday but a rebellion by 148 of his 359 Conservative Party lawmakers dealt a serious blow to his authority. A majority of the Conservatives’ lawmakers – at least 180 – would have had to vote against Johnson for him to be removed. The result means Johnson secured the backing of 59% of his lawmakers, lower than the support given to his predecessor Theresa May in a confidence vote she faced in 2018. Having scored a sweeping election victory in 2019, the prime minister has …