It's moderately safe......but unlikely to be very effective. Spraying anything is unlikely to be very effective because the miners are a fly larvae that lives and feeds within the plant tissue. Topical sprays regardless of ingredients will have no effect unless they can also penetrate the plant tissue. And unless a systemic, they cannot. After the removal of any infected leaves, your best control is to cover the plants with a row cover.

Any dish soap used on plants should be a castile soap or one without any detergents. And you would still want to wash any produce well before eating anyway, so the safety issue is more with the plants than with you :-))

The word "galore" should be used more often.

FWIW, when dealing with leaf miners, I pinch the leaf to squish the larvae. They're usually found at the end of the 'mine' tunnel, a teeny, tiny little blob.