A Randomized Phase 2, Investigator-Led Trial of Glofitamab-R-CHOP or Glofitamab-Polatuzumab Vedotin-R-CHP (COALITION) in Younger Patients with High Burden, High-Risk Large B-Cell Lymphoma Demonstrates Safety, Uncompromised Chemotherapy Intensity, a High Rate of Durable Remissions, and Unique FDG-PET Response Characteristics