fix: ex is declared but never used

CarManagerV2/ImageManager.cs

@@ -63,7 +63,7 @@ namespace CarManagerV2
                 {
                     client.DownloadFile(url, path);
                 }
-                catch (Exception ex)
+                catch 
                 {
                     // if error, use no_image_available.png
                     System.IO.File.Copy("images/no_image_available.png", path);