Ouch, actually it appears, that AI mods don’t work in scenario editor. They only work in standard game and multiplayer. I have posted a bug report about it, but no one has reacted to it in 5 months.
I got “No unit movement” AIs to appear in scenario editor by copying files from “C:\Users\{username}\Games\Age of Empires 2 DE\{userId}\mods\subscribed\820_AI - No Unit Movement\resources\_common\ai” to “Steam\steamapps\common\AoE2DE\resources\_common\ai”.
I tested this AI and it works.
But because you are using Windows Store version (that version prevents access to its files) you probably can’t access game AI files folder, so this fix won’t work for you 