TRACKS: Modifying an animated actor with no keys doesn't update the defaults.

When modifying the transform or properties of an animated object with no keys, the default values for the animation tracks should be updated.

1. Create a level sequence.
2. Add an actor to it.
3. Add a transform track.
4. Delete the keys.
5. Disable auto-key
5. Move the actor in the viewport.
6. Move the playback position.
Result: The actor snaps back to the previous location.
Expected Result: When there are no keys, the actor's default animated position should be updated.