Changes to MailSendService

originally we had the trader id -> then used a method to get the EnumValue as a string -> then later turned it BACK into a traderId

unless im missing something major this should simplify things?

example:
we took "6617beeaa9cfa777ca915b7c" and turned it to "Ref" to then turn it back to "6617beeaa9cfa777ca915b7c"

Libraries/SPTarkov.Server.Core/Controllers/TradeController.cs

@@ -320,7 +320,7 @@ public class TradeController(
         // Send mail from trader
         _mailSendService.SendLocalisedNpcMessageToPlayer(
             sessionId,
-            _traderHelper.GetTraderById(trader).ToString(),
+            trader,
             MessageType.MESSAGE_WITH_ITEMS,
             _randomUtil.GetArrayValue(_databaseService.GetTrader(trader).Dialogue.TryGetValue("soldItems", out var items) ? items : new List<string>()),
             curencyReward.SelectMany(x => x).ToList(),