Show Immature Balance in walletsend page (#2731)

* Wallet Send page also shows immature balance

* changes ans to and

* Immature Balance msg is not tooltip

* Make msg more clear

BTCPayServer/Models/WalletViewModels/WalletSendModel.cs

@@ -35,6 +35,7 @@ namespace BTCPayServer.Models.WalletViewModels
             public bool SubtractFeesFromOutput { get; set; }
         }
         public decimal CurrentBalance { get; set; }
+        public decimal ImmatureBalance { get; set; }
 
         public string CryptoCode { get; set; }