SERVER-77911 introduced a change where the shard merge importer service set the 'historicalIDTrackerAllowsMixedModeWrites' decoration to true. However, during the process of moving the method (importCollectionAndItsIndexesInMainWTInstance()) responsible for setting this decoration from 'tenant_migration_shard_merge_util.cpp' to 'tenant_file_importer_service.cpp,' SERVER-74585 inadvertently removed that modification.