Fix loading locale in setup (#21651)

frontend/src/metabase-types/api/mocks/settings.ts

frontend/src/metabase-types/api/settings.ts

frontend/src/metabase-types/store/forms.ts

frontend/src/metabase-types/store/index.ts

frontend/src/metabase-types/store/mocks/forms.ts

frontend/src/metabase-types/store/mocks/index.ts

frontend/src/metabase-types/store/mocks/setup.ts

frontend/src/metabase-types/store/mocks/state.ts

frontend/src/metabase-types/store/setup.ts

frontend/src/metabase-types/store/state.ts

frontend/src/metabase/entities/users/forms.js

frontend/src/metabase/setup/actions.ts

...c/metabase/setup/components/DatabaseStep/DatabaseStep.tsx

.../setup/components/DatabaseStep/DatabaseStep.unit.spec.tsx

...c/metabase/setup/components/LanguageStep/LanguageStep.tsx

.../setup/components/LanguageStep/LanguageStep.unit.spec.tsx

...tabase/setup/components/NewsletterForm/NewsletterForm.tsx

frontend/src/metabase/setup/components/UserStep/UserStep.tsx

...metabase/setup/components/UserStep/UserStep.unit.spec.tsx

...src/metabase/setup/components/WelcomePage/WelcomePage.tsx