* Basic mobs can emote when they get a new target (#76654)
## About The Pull Request
Fixes#76624
Restores lost functionality for a mob to play an emote when it acquires
a new target.
Also I added a generic blackboard key change signal which could
potentially have other uses in the future.
## Why It's Good For The Game
It's good feedback to know when a mob has chosen to target something.
## Changelog
🆑
fix: Carp, Trees, and Festivus Poles will once more sometimes emote at
you if they think you are looking at them the wrong way, before they
come over to beat you up.
/🆑
* Basic mobs can emote when they get a new target
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Co-authored-by: Jacquerel <hnevard@gmail.com>
