[pistache-server]: does not generate required object fields

Description

When generating pistache-server code, non-primitive, non-string, non-datetime objects that are marked as required are not taken into account when generating with the fromJson method.

Swagger-codegen version

Latest release

Swagger declaration file content or url

Refer to pet documentation example, line #150
https://github.com/swagger-api/swagger-codegen/blob/master/samples/yaml/pet.yml#L150
If you add category to the required fields, this bug should appear in the pistache-server generation.

Command line used for generation

docker run --rm -v ${PWD}:/local -u $(id -u):$(id -g)
swaggerapi/swagger-codegen-cli generate
-i /local/crs_api_spec.yaml
-l pistache-server
-o /local/generated

Steps to reproduce

Generate a non-primitive, non-string, non-datetime object within an object, and mark it as a required field.
Serialize object and deserialize object from json.
Observe different JSON.

Related issues/PRs

Hopefully, this is fixed in #10228 but have not FULLY confirmed due to maven build locally failing with over 100 tests unrelated to the mustache change I made.

Start with the pistache-server generation path and the fromJson method, using the pet.yml example at line 150 to reproduce the required category case. Compare the serialized and deserialized JSON for a required nested object, and review related PR #10228 and its Mustache change before deciding whether the issue remains. Done means required non-primitive fields are preserved through deserialization.