removed error when invalid plugin. It was called even when a typo was made

PluginManager/Bot/CommandHandler.cs

@@ -126,8 +126,7 @@ internal class CommandHandler
             }
             
             if (plugin is null)
-                throw new Exception("Failed to run command ! " + message.CleanContent + " (user: " +
-                                    context.Message.Author.Username + " - " + context.Message.Author.Id + ")");
+                return;
 
             if (plugin.requireAdmin && !context.Message.Author.isAdmin())
                 return;