A few drops in the water won't hurt them. You can follow up with a good drench with clear water if you want. Dish soap is really mild, but it's a good wetting agent - so makes the "drowning effect" on the bugs more efficient. (Do you get the impression that I get sadistic pleasure in dispatching bugs and slugs and such? I do...
) It might even make water (and fertilizer) uptake by the plant more efficient... I wouldn't use it routinely, but a bit will do no harm.