Refactor PaymentMethodsUseCase to use a stateful state, instead of be…#2822

amy-at-kickstarter wants to merge 2 commits intomainkickstarter/ios-oss:mainfrom

feat/adyer/refactor-use-case-statefulkickstarter/ios-oss:feat/adyer/refactor-use-case-statefulCopy head branch name to clipboard