I would compost it. Some larvae are [probably in the soil anyway. When you think, the miner arrives originally without anyone spreading compost containing the larvae. In a similar vein, I had lots of leek moth here last year,in a brand new garden. And even for moth the official advice is to dispose of debris, but I compost it.
As for so many vegetables, good results come from improving their vigour by growing them in well-composted soil. You can’t now be rid of leaf miner but you can help leeks grow well in spite of it. Possibly cover with mesh too.