Makes logic check both connection sandbox mode and request params for the dev flag

Previously logic was only considering the client sandbox mode.

This change allows passing this flag either as a request parameter or
specifying the sandbox mode for a connection.

Author: ZloeSabo

src/kraken-net-v2/Http/Connection.cs

@@ -78,7 +78,7 @@ internal async Task<IApiResponse<TResponse>> Execute<TResponse>(ApiRequest apiRe
         {
             apiRequest.Body.Authentication.ApiKey = _apiKey;
             apiRequest.Body.Authentication.ApiSecret = _apiSecret;
-            apiRequest.Body.Dev = SandboxMode;
+            apiRequest.Body.Dev = SandboxMode || apiRequest.Body.Dev;
             var isSet = apiRequest.Body is IOptimizeSetWaitRequest || apiRequest.Body is IOptimizeSetUploadWaitRequest;
 
             using (var requestMessage = new HttpRequestMessage(apiRequest.Method, apiRequest.Uri))
@@ -102,7 +102,7 @@ internal async Task<IApiResponse<TResponse>> ExecuteUpload<TResponse>(
 
             apiRequest.Body.Authentication.ApiKey = _apiKey;
             apiRequest.Body.Authentication.ApiSecret = _apiSecret;
-            apiRequest.Body.Dev = SandboxMode;
+            apiRequest.Body.Dev = SandboxMode || apiRequest.Body.Dev;
             var isSet = apiRequest.Body is IOptimizeSetWaitRequest || apiRequest.Body is IOptimizeSetUploadWaitRequest;
 
             using (

src/kraken-net/Http/Connection.cs

@@ -78,9 +78,9 @@ internal async Task<IApiResponse<TResponse>> Execute<TResponse>(ApiRequest apiRe
         {
             apiRequest.Body.Authentication.ApiKey = _apiKey;
             apiRequest.Body.Authentication.ApiSecret = _apiSecret;
-            apiRequest.Body.Dev = SandboxMode;
+            apiRequest.Body.Dev = SandboxMode || apiRequest.Body.Dev;
             var isSet = apiRequest.Body is IOptimizeSetWaitRequest || apiRequest.Body is IOptimizeSetUploadWaitRequest;
-               
+
             using (var requestMessage = new HttpRequestMessage(apiRequest.Method, apiRequest.Uri))
             {
                 var json = JsonConvert.SerializeObject(apiRequest.Body, _serializerSettings);
@@ -102,7 +102,7 @@ internal async Task<IApiResponse<TResponse>> ExecuteUpload<TResponse>(
 
             apiRequest.Body.Authentication.ApiKey = _apiKey;
             apiRequest.Body.Authentication.ApiSecret = _apiSecret;
-            apiRequest.Body.Dev = SandboxMode;
+            apiRequest.Body.Dev = SandboxMode || apiRequest.Body.Dev;
             var isSet = apiRequest.Body is IOptimizeSetWaitRequest || apiRequest.Body is IOptimizeSetUploadWaitRequest;
 
             using (