Fix for Charge.test serialization

[clement911]

Ensure that Charge.Test and RecurringCharge.Test property is always serialized so that the FalseToNullConverter can kick in.

The FalseToNullConverter wasn't kicking in because the serializer uses NullValueHandling.Ignore
This is fixed by applying NullValueHandling.Include at the property level.

I personally think this converter should be removed altogether, but some people might rely on the fact that this the Test property should always return either false or true and never null. The API seems to accept false values.

Maybe we can remove FalseToNullConverter.cs altogether in the major/breaking release.

[nozzlegear]

I agree, this seems like a good one to remove in 6.0.

[clement911]

thanks. looks like you did a great job with respect to the build pipeline and release workflow. very easy to use!

[nozzlegear]

Glad you like it! I want to take another look at the pipeline soon so that both of us can approve full releases to nuget for Minor and Patch releases, but require reviews/approval for Major releases. I'm pretty sure that's possible but I need to review the github actions docs and figure out how to incorporate it in the scripts.