fix: С# client generation is missing default values for parameters

[renatosc]

This is a fix for #3697 and #4010

[renatosc]

@RicoSuter @lahma when you have time. And Thank you for the work on this repo.

[renatosc]

I am checking the tests

[renatosc]

I think I may need so guidance with those tests.

For example, I look at that windows-latest fail. It says that " NSwag.CodeGeneration.CSharp.Tests.ClientGenerationTests.CanGenerateFromJiraOpenApiSpecification [FAIL]" because the JIRA_OpenAPI.received.txt is not the same as JIRA_OpenAPI.verified.txt

My understanding is that the test CanGenerateFromJiraOpenApiSpecification is using the jira-open-api.json as the openapi schema source.

I got the contents of that file and I generated the csharp client using NSwagStudio compiled from main branch and also from my PR branch. Both generated clients have the same contents which were equal to the JIRA_OpenAPI.verified.txt file.

I also ran the build Compile Test Pack locally and all tests are passing.

Any idea on where I should look at?