fix: Only clear log on connect, not disconnect

Author: tuxuser

PostCodeSerialMonitor/ViewModels/MainWindowViewModel.cs

@@ -360,11 +360,9 @@ private async Task ToggleConnectionAsync()
             else
             {
                 await _serialService.ConnectAsync(SelectedPort.Name);
+                ClearLog();
                 IsConnected = true;
             }
-
-            RawLogEntries?.Clear();
-            LogEntries?.Clear();
         }
         catch (Exception ex)
         {