A Phase III, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study Evaluating the Efficacy and Safety of Inavolisib in Combination with Phesgo Versus Placebo in Combination with Phesgo as Maintenance Therapy After First Line Induction Therapy in Participants with PIK3CA Mutated HER2 Positive Locally Advanced or Metastatic Breast Cancer