Spawned skeletal animations don't animate

1. In 4.17, create a level sequence with a skeletal animation and a skeletal animation track
2. Open that level sequence in 4.18 and record it to a movie
   Result: The skeletal animation doesn't animate
   Expected: The skeletal animation animates

There's no bug if step #1 is using 4.18 because there's a fix for the bug in 4.18 (dragging in a skeletal animation as a spawnable). But I think some flag in 4.17 got introduced that sets the actor to be an editor preview actor.