fix: Duplicate call to Disconnected handler

Author: tuxuser

PostCodeSerialMonitor/Services/SerialService.cs

@@ -298,7 +298,8 @@ internal void ReadLoop(CancellationToken token)
         }
         catch (Exception)
         {
-            Disconnected?.Invoke();
+            if (!token.IsCancellationRequested)
+                Disconnected?.Invoke();
         }
     }