Update to UE4.25.4

[yhyu13]

Hi, I've enjoyed your work but since you haven't kept it update to the latest, I decided to do it on my own.

There are a few really helpful guidance out there already: https://www.unrealengine.com/marketplace/en-US/product/don-s-3d-pathfinding-flying-ai/questions
And
https://forums.unrealengine.com/community/community-content-tools-and-tutorials/74866-don-s-3d-pathfinding-flying-ai-system-with-full-source?102933-DoN-s-3D-Pathfinding-Flying-AI-system-(with-full-source!)/=&q=4.24

Also, please upgrade your UE4.25 to at least 4.25.1 version because:

UE4.25.0 introduced an error in AI Blackboard component upon stopping the in-editor game mode:
https://forums.unrealengine.com/development-discussion/blueprint-visual-scripting/5331-behavior-tree-gotchas
That has been fixed later with a github commit:
https://github.com/EpicGames/UnrealEngine/commit/d1de12ca8c5d44839a72a6328968deac06c92837
And the bug tracking:
https://issues.unrealengine.com/issue/UE-92936

I managed to run your 4.15 sample project by replacing this update to date plugin.

Thank you!