Caused by rBcfa53e0fbeed: Refactor: Move normals out of MVert, lazy calculation

Above commit mixed up source and destination meshes causing bad lookups
on calculated normals.

Now make sure we get normals from our destination mesh to project along.

Note this was only reported for Projected Face Interpolated mode, but
same was true for Projected Edge Interpolated mode (though that one is a
bit weird to test since I think there is generally something wrong with
that mode -- with or without rBcfa53e0fbeed).

Fixes T97528