enhance: avoid refetch avatar for noreply@github.com

src/Models/AvatarManager.cs

@@ -122,6 +122,9 @@ namespace SourceGit.Models
         {
             if (forceRefetch)
             {
+                if (email.Equals("noreply@github.com", StringComparison.Ordinal))
+                    return null;
+
                 if (_resources.ContainsKey(email))
                     _resources.Remove(email);
 

src/Views/Avatar.cs

@@ -39,10 +39,7 @@ namespace SourceGit.Views
             refetch.Click += (_, _) =>
             {
                 if (User != null)
-                {
                     Models.AvatarManager.Request(User.Email, true);
-                    InvalidateVisual();
-                }
             };
 
             ContextMenu = new ContextMenu();