Remove UnrealEngine due to token error

Author: brendan-kellam

demo-site-config.json

@@ -522,7 +522,6 @@
                 "SortableJS/Sortable",
                 "v2fly/v2ray-core",
                 "open-mmlab/mmdetection",
-                "EpicGames/UnrealEngine",
                 "vuejs/vue-cli",
                 "webtorrent/webtorrent",
                 "layui/layui",