The answer depends on why you’re doing the fast. If you’re fasting for autophagy, gut health, etc., then yes zero calorie drinks will likely break a fast. Artificial sweeteners (even though they’re 0 calories) can still stimulate an insulin response, which would theoretically interrupt autophagy and break the fast.
If you’re fasting only for weight loss, it’s probably fine.
I can tell you from first hand experience that they wont break ketosis. As far as breaking a fast…even if they did. You would be right back in the fast in less than 10 mins. There is almost nothing for the body to process.