InitializeAnimScriptInstance may only need to be called if the mesh actually changes when restoring state in Sequencer

The fix for [Link Removed] reinitializes the anim bp whenever the animation section restores state, it may only be necessary to reinitialize it if the skeletal mesh changes.

1. Create a sequence that has a skel mesh with an animation on it that uses an anim bp
2. Set the animation section to restore state when finished
3. Add a node for Event Blueprint Initialize Animation in the anim bp's event graph, and have it print something
4. Scrub past the end of the animation in the level sequence

RESULT

The anim bp will print the text, as the animation bp is reinitialized, even if the skeletal mesh hasn't changed.