Fix Updater Icon On Linux (#1995)

* Fix Linux Icon

* Fix identation

* Move the icon to the private constructor

Ryujinx/Modules/Updater/UpdateDialog.cs

@@ -5,6 +5,7 @@ using Ryujinx.Ui;
 using System;
 using System.Diagnostics;
 using System.Linq;
+using System.Reflection;
 using System.Runtime.InteropServices;
 
 namespace Ryujinx.Modules
@@ -32,6 +33,7 @@ namespace Ryujinx.Modules
             _mainWindow = mainWindow;
             _buildUrl   = buildUrl;
 
+            Icon = new Gdk.Pixbuf(Assembly.GetExecutingAssembly(), "Ryujinx.Ui.Resources.Logo_Ryujinx.png");
             MainText.Text      = "Do you want to update Ryujinx to the latest version?";
             SecondaryText.Text = $"{Program.Version} -> {newVersion}";
 
@@ -86,4 +88,4 @@ namespace Ryujinx.Modules
             Dispose();
         }
     }
-}
+}