Utils: Add User-Agent to default http client

Elwig/Helpers/Utils.cs

@@ -23,7 +23,6 @@ using System.Reflection;
 using System.Collections;
 using Elwig.Documents;
 using MimeKit;
-using System.Windows.Input;
 using LinqKit;
 using System.Linq.Expressions;
 using Elwig.Models;
@@ -430,6 +429,8 @@ namespace Elwig.Helpers {
             var client = new HttpClient() {
                 Timeout = TimeSpan.FromSeconds(5),
             };
+            client.DefaultRequestHeaders.UserAgent.Clear();
+            client.DefaultRequestHeaders.UserAgent.ParseAdd($"Elwig/{App.Version} ({App.Client.NameToken}, {App.BranchName}, {Environment.MachineName}, {Environment.OSVersion})");
             client.DefaultRequestHeaders.Accept.Clear();
             if (accept != null)
                 client.DefaultRequestHeaders.Accept.Add(new(accept));