odometers property Null safety

Implementation

@override
@Rest(
  toGenerator:
      'SyncGeneratorHelper.engineModelToSqlOrRest(%INSTANCE_PROPERTY%)',
  fromGenerator:
      'SyncGeneratorHelper.sqlOrRestToEngineModel<RunLocationOdometer>'
      '(RunLocationOdometer.odometerFromJson, %DATA_PROPERTY%)',
)
@Sqlite(
  columnType: Column.varchar,
  toGenerator:
      'SyncGeneratorHelper.engineModelToSqlOrRest(%INSTANCE_PROPERTY%)',
  fromGenerator:
      'SyncGeneratorHelper.sqlOrRestToEngineModel<RunLocationOdometer>'
      '(RunLocationOdometer.odometerFromJson, %DATA_PROPERTY%)',
)
final RunLocationOdometer odometers;