No, it's not necrophilia -- that's with an inanimate corpse.
Whether this counts as *in*necrophilia even if she *is* a Puella Magi is a question that I don't have a clear answer to. (It depends on what you define as "living", and depending on that, it might also depend on aspects of Puella Magi that we don't know about)
Not that it's clear that she's a Puella Magi in this scene anyway. (it's likely, but not certain).
