fix issue with default migrationContext
fix issue with default migrationContext

Signed-off-by: Phani Raj <e32426b86e9fbdda17f4aa1aca45727ffe36415d@planetscale.com>

mahak/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,mahak/vitess,mahak/vitess,vitessio/vitess,mahak/vitess,mahak/vitess,vitessio/vitess,vitessio/vitess