Register not allow name with empty spaces

Author: rxtur

src/App/Pages/Admin/Settings/Register.cshtml.cs

@@ -13,6 +13,7 @@ public class RegisterModel : AdminPageModel
         #region Properties
 
         [Required]
+        [RegularExpression(@"^\S*$", ErrorMessage = "No white space allowed")]
         [BindProperty]
         public string UserName { get; set; }