Using Conversion 2 against Fury Swipes will randomly change Porygon2 into either Rock, Steel, or Ghost type (unless you already have one of those types, in which case it'll be excluded from consideration and the random choice will only be among the others). Shedinja being the move user has absolutely no relevance to the scenario, and this isn't a very productive payoff; neither of the Conversion moves can do anything to change the type of a Pokemon other than the one who's using the move.
Porygons have been known to use the original Conversion with Shadow Ball in the first moveslot if they really want to become a ghost, and that doesn't rely on either randomness or having a teammate, let alone one who spends their turn using a weak Normal move.