Really always validate when app.testing == True

The docs say that this field will always validate with app.testing == True. I think this is a good thing. However, the current behavior doesn't reflect this. If there is no input, it doesn't validate. It should validate, though. Testing systems might not have any kind of recaptcha key set up in which case the widget will not display and you can't put any input into there.

Hence, we should simply always validate on app.testing == True.