Workflow SDK - Add System.Text.Json default options

[tomflenner]

Describe the feature

We would like the ability to configure default System.Text.Json options in the Dapr .NET SDK, such as custom JsonConverters for example.

This feature would enable developers to apply default STJ configuration behavior.

It could be implemented by exposing a way to register global JsonSerializerOptions, or at least a hook to customize or extend the default behavior.

Use case examples:

• Add a default JsonConverter for polymorphic deserialization.

This is particularly useful for applications that already use System.Text.Json and want Dapr SDK to align with their existing serialization logic.

Release Note

RELEASE NOTE: ADD Support for configuring default System.Text.Json options (e.g., converters, naming policy) in the Dapr .NET SDK.

[tomflenner]

Additional : we can override STJ configuration in Dapr client for example (from the doc https://docs.dapr.io/developing-applications/sdks/dotnet/dotnet-client/dotnet-daprclient-usage/#dependency-injection)

services.AddDaprClient(daprBuilder => {
    daprBuilder.UseJsonSerializerOptions(new JsonSerializerOptions {
            WriteIndented = true,
            MaxDepth = 8
        });
    daprBuilder.UseTimeout(TimeSpan.FromSeconds(30));
});

But it's not the case for Workflow/Activity STJ usage.