Constraint Binding ID is broken on attach track when subsequence asset is moved.

Moving a level sequence asset that contains actors that are being referenced as a subsequence in an attach track causes the references to drop, even though the subsequence reference is correctly updated. Notably, moving the file BACK to the original location restores the references.

Steps to Reproduce

1. Create two level sequences, e.g. "Inner" and "Outer"
2. In the "Inner" one, place any actor, e.g. InnerActor; optionally add some transform keys to animate it
3. In the "Outer" one, place the "Inner" one as a subsequence
4. In the "Outer" one, place another actor, add an attach track to it, and attach it to the InnerActor inside the Inner subsequence (this e.g. would represent rigging a camera to an animated actor)
5. Once everything is saved and working, move the Inner sequence asset in the Content browser to another folder

Result: While the Outer LS retains the reference to the Inner LS subsequence, the attachment disappears.