A PHASE I, OPEN-LABEL STUDY TO EVALUATE THE SAFETY, TOLERABILITY, PHARMACOKINETICS, PHARMACODYNAMICS, AND ANTI-TUMOR ACTIVITY OF RO7589831 AS MONOTHERAPY AND IN COMBINATION WITH PEMBROLIZUMAB IN PARTICIPANTS WITH ADVANCED SOLID TUMORS HARBORING MICROSATELLITE INSTABILITY (MSI) AND/OR DEFICIENT MISMATCH REPAIR (DMMR)