Describe the bug
RestClient default headers added to the RestClient are not included in RestRsponse.Request.Parameters collection when using RestClient.AddDefaultHeader method
To Reproduce

RestClient restClient = new RestClient("https://swapi.dev/api");
restClient.AddDefaultHeader("Authorization", "1234");
RestRequest rq = new RestRequest("/films", Method.Get);
RestResponse rs = restClient.Execute(rq); `
Expected behavior
RestClient default headers should be included in the RestResponse.Request.Parameters collection
Stack trace
No exceptions; just missing data
Desktop (please complete the following information):
- OS: Windows
- .NET 6
- RestSharp v112