A Phase 3, Randomized, Placebo-Controlled, Double-Blind Clinical Study Of Pembrolizumab (MK-3475) With Or Without Lenvatinib (E7080/MK-7902) To Evaluate The Safety And Efficacy Of Pembrolizumab And Lenvatinib As 1L Intervention In A PD-L1 Selected Population Of Participants With Recurrent Or Metastatic Head And Neck Squamous Cell Carcinoma (R/M HNSCC) (LEAP-010)