Case C-427/21, ALB FILS KLINIKEN: Judgment of the Court (Sixth Chamber) of 22 June 2023 (request for a preliminary ruling from the Bundesarbeitsgericht — Germany) — LD v ALB FILS Kliniken GmbH (Reference for a preliminary ruling — Social policy — Temporary agency work — Directive 2008/104/EC — Article 1 — Scope — Definition of ‘temporary assignment’ — Transfer of duties performed by a worker, from the latter’s employer to a third-party undertaking — Permanent assignment of that worker while maintaining the latter’s initial contract of employment)