Remove HttpStatusCode=OK from WriteAsJsonAsync

[RohitRanjanMS]

Eliminated the default value for HttpStatusCode and removed the overloaded methods for setting HttpStatusCode in the response.

Default Behavior - 200 OK

var responseData = req.CreateResponse();
await responseData.WriteAsJsonAsync(new { message = "Done" });
return responseData;

Return a non-200 response

var responseData = req.CreateResponse(HttpStatusCode.BadRequest);
await responseData.WriteAsJsonAsync(new { message = "An error occurred" });
return responseData;

resolves #776

This is a breaking change, targeting feature/2.x branch.

Pull request checklist

• My changes do not require documentation changes
  • Otherwise: Documentation issue linked to PR
• My changes should not be added to the release notes for the next release
  • Otherwise: I've added my notes to release_notes.md
• My changes do not need to be backported to a previous version
  • Otherwise: Backport tracked by issue/PR #issue_or_pr
• I have added all required tests (Unit tests, E2E tests)

[fabiocav]

@RohitRanjanMS can you please update the release notes with the change details?

[soninaren]

Can you update the release notes before merging.