This is not a very elegant solution, but if this is really frustrating for you then this will help you.
You can create a new bookmark in your browser and in the address field add this code:
Whenever you open a codecademy exercise just click on the bookmark and the auto-closing of brackets, parentheses and quotes will be disabled. But you have to click the bookmark every time you open the exercise.
If you use Codecademy extensively and you don’t want to click on the bookmark every 5 minutes then you can add this code as a custom user script using, for example, tampermonkey or witchcraft.