Use registred CustomSerializer for Criteria-Objects

[jensbrand]

Summary

• Problem: Criteria objects not inheriting from IMobileObject bypass registered custom serializers, causing serialization errors.
• Solution: Refactored PrimitiveCriteria into a ReadOnlyBase and updated DataPortalProxy to instantiate it via the data portal.
• Result: Criteria objects now serialize like standard properties and correctly utilize custom serializers.

Related Issue

Fixes #4865 (Custom Serializer for Criteria-Objects)

[StefanOssendorf]

Hi. Thank you for your contribution.

However I think this is the wrong approach to solve this issue. The PrimitiveCriteria was meant to deal with the .net primitives (int, string, DateTime, ...) and not with custom serializers.

I think the correct way would be something like adding a way to ISerializationFormatter to ask if it can check a particular type.
If yes: Skip PrimitiveCriteria
If no: Use PrimitiveCriteria

But this is something more fundamental where I'd like to get @rockfordlhotka opinion this. Your way works, maybe as a temporary implementation, but it should be implemented in another way for the future.