Add JsonSerializerContext support

[baliestri]

This pull aim to solve an issue in GrafanaLoki where the sink fails to serialize the LokiBatch object when reflection-based JSON serialization is disabled in .NET 8.0+ (i.e., when JsonSerializerIsReflectionEnabledByDefault is set to false). The problem originates in the LokiBatch.cs file, where JsonSerializer.Serialize lacks proper JsonTypeInfo metadata for reflection-free serialization.

Fixes #297

[mishamyte]

Hi @baliestri,

Thanks for finding and contribution.
I'm wondering would it work correctly without JsonSerializerContext for LokiStream model too?

[baliestri]

Thanks for finding and contribution. I'm wondering would it work correctly without JsonSerializerContext for LokiStream model too?

Yeah, if you open the generated code you will see the LokiStream already serialized, it generates for each type inside of the object you said it should serialize. So the LokiStream will receive a JsonTypeInfo too.