Address review feedback: revert global.json and delete CollectionExtensions files

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Author: Copilot

global.json

@@ -1,5 +1,5 @@
 {
   "sdk": {
-    "version": "8.0.115"
+    "version": "8.0.406"
   }
 }