[header] changed translate input type

CHANGELOG.md

MIGRATION.md

...nents/src/lib/components/header/header-translate.model.ts

...omponents/src/lib/components/header/header.component.html

...-components/src/lib/components/header/header.component.ts

...fr-components/src/lib/components/header/header.stories.ts

...ts/ngx-dsfr-components/src/lib/components/header/index.ts