Async auch UTF8

Shared/AppSender/AppRequestSender.cs

@@ -95,6 +95,8 @@ namespace BS.Shared.AppSender
 
 			using (WebClient client = new WebClient())
 			{
+				client.Encoding = Encoding.UTF8;
+
 				client.Headers.Add(HttpRequestHeader.ContentType, "application/json");
 
 				response = await client.UploadStringTaskAsync(url, "POST", dataString);