Aquatic mystery snails are NOT something pacs eat in the wild to my knowledge... All snails are not the same thing. I personally wouldn't, but it's your call. Most things with mucous membranes produce some sort of mild toxin; since the frog hasn't evolved to eat this snail specifically, you may run the risk of exposing the frog to toxins.

Also I would not feed adults with the shell hardened. You have calcium powder; why risk a shell breaking and harming your frog, or the shell not digesting properly?

Again, this sort of thing is the individual keeper's call. In all likelihood nothing bad will happen, but I'm throwing out worst-case-scenarios