Updates Pull Payment Payment Method (#3107)

* adds checkbox to pull payment

* adds label improvement

* removes "back to list"

* Remove superfluous style block

Seems to be a copy and paste remainder

* Make custom CSS additional options

* Fix input name and test

* Improve display for case with only one payment method

* Fix test

Co-authored-by: Dennis Reimann <mail@dennisreimann.de>

BTCPayServer/Models/WalletViewModels/PullPaymentsModel.cs

@@ -49,6 +49,7 @@ namespace BTCPayServer.Models.WalletViewModels
         [Display(Name = "Custom CSS Code")]
         public string EmbeddedCSS { get; set; }
 
+        [Display(Name = "Payment Methods")]
         public IEnumerable<string> PaymentMethods { get; set; }
         public IEnumerable<SelectListItem> PaymentMethodItems { get; set; }
     }