Elsa 3 no way to change response serialization case to match entities

Currently there is no way to return activity data via and endpoint response that matches the internal pascal case of the entity classes. 

We have internal entities that we use in custom activities. Many of the activities return these entities to the client via endpoint responses.Right now the entities are always returned in camel case with no way to change the default behavior to pascal to match the entity case, which can then create issues when using property data for any further activities. 

No file, test, or entry point is named. Start by tracing how endpoint responses serialize activity entities and identify where the default camel-case behavior is configured. Done means callers can select PascalCase serialization for these responses while preserving the existing default behavior.

Written by the indexing model from the issue text.