Phase II study: a study to explore the safety and preliminary efficacy of BAT1308 combined with platinum-based chemotherapy ± Bevacizumab Phase III study: a confirmatory study to evaluate the safety and efficacy of BAT1308 combined with platinum-based chemotherapy ± Bevacizumab as first-line therapy for PD-L1-positive (CPS ≥ 1) persistent, recurrent or metastatic cervical cancer