Fix AmateurTest LocaleAssignment offenses
Fix AmateurTest LocaleAssignment offenses

Fix Rails/I18nLocaleAssignment offenses in AmateurTest.
Use `with_locale` blocks instead of switching local with `locale =`

MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer