Python: [Feature]: Allow a global registry of checkpoint allow types

[TaoChenOSU]

Description

We should allow a global registry of checkpoint deserialization allow types, similar to what Agent session already has: https://github.com/microsoft/agent-framework/blob/main/python/packages/core/agent_framework/_sessions.py#L506

This will allow applications to use the build-in checkpoint storage while not directly owning the storage.

Code Sample

Language/SDK

Python