Case C-151/21: Order of the Court (Eighth Chamber) of 13 December 2021 (request for a preliminary ruling from the Tribunal Superior de Justicia de Castilla-La Mancha — Spain) — Servicio de Salud de Castilla-La Mancha (SESCAM) v BF (Framework agreement on fixed-term work concluded by ETUC, UNICE and CEEP — Clause 4 — Principle of non-discrimination — Field of public health — Calculation of length-of-service increments — National legislation refusing to take into account, as regards permanent staff regulated under administrative law, for the purpose of calculating length-of-service increments, periods corresponding to activities temporarily exercised in a higher professional category)