For polymorphic (de)serialization, use default serializer if `type` property is ommited.

[paloliska]

Describe the problem you'd like to solve

If there is polymorphic default serializer, I would like to use it not only for unknown classes, but also, when class is not defined. For example, if property style polymorphism is defined and type property is not defined in input yaml.

Describe the solution you'd like

I would like to save some lines in source yaml file.

Describe alternatives you've considered

No response

Additional context

No response