fix(header): problème d'alignement des liens rapides

...lib/components/header/demo/demo-header-focus.component.ts

...nents/src/lib/components/header/header-menu-item.model.ts

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

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

...dsfr-components/src/lib/components/header/header.model.ts

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

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

...components/src/lib/components/link/item-link.component.ts

...dsfr-components/src/lib/components/link/link.component.ts