By Saikat Chatterjee and Samuel Indyk LONDON (Reuters) – British markets braced on Wednesday for more political drama, as Prime Minister Boris Johnson was rocked by further ministerial resignations and calls for him to go, although traders were reluctant to take new positions given the uncertainty. Bookmakers have slashed odds on Johnson’s imminent departure and analysts said markets had largely priced in his exit after a series of scandals, including accusations that he breached his own COVID-19 lockdown rules, weakened his authority. The pound dropped to more than two-year lows against the d…