[#6885] Fix MemoryStream Converter when serializing

[sw-joelmut]

Fixes #6885

Description

This Pr fixes an issue when adding and removing the converter to the JsonSerializer over multiple threads, causing fail due to null assignment.

Specific Changes

• Replaced WriteJson functionality from assigning the converter recursively to instead call the WriteJson recursively to serialize the object.
• Updated HaveStreams method to work with both Read and Write json.
• WriteJson and HaveStreams methods now share similar behavior, detecting Dictionaries, Collections, and Classes separately.

Testing

The following image shows the unit tests continue working correctly.