Socket Snapping in level editor no longer works

The Socket Snapping level editor action no longer works in 4.19/4.20, it worked in 4.18 but regressed. It still attaches but it's set to maintain it's world position, so it doesn't actually snap.

This broke in CL #3692526 from AnimPhys. ParentActors used to snap if a socket was selected, which is depended on by ClickLevelSocket. There should probably be an option to ParentActors saying rather to snap, instead of changing the default one way or the other

The work around is to use socket snapping, then manually reset the relative location/rotation to snap it, but this is much slower than the old method

1. Place a skeletal mesh with sockets in a level
2. Place a static mesh in a level, change it to Movable
3. Go to Settings and enable Socket Snapping. This should cause a grey diamond to appear for every socket on the skeletal mesh
4. Select the static mesh, then left click a grey diamond
5. The static mesh will be attached to the socket but will NOT snap to it. In 4.18 it snapped