In Jain Dharma, onion is generally not eaten, and onion leaves are also usually avoided.

Reason: Jain dietary discipline avoids root vegetables and bulb plants like onion, garlic, potato, etc., because they are believed to involve more violence to the plant and to contain more life.

So the simple answer is: No, Jains generally should not eat onion leaves either.

If you want, I can also explain the Jain reason in a very simple way.