Revert "Add packageManager field to package.json"

This reverts commit 94c3ac3.

Author: NullVoxPopuli

files/package.json

@@ -76,7 +76,6 @@
     "typescript-eslint": "^8.19.1<% } %>",
     "vite": "^7.1.9"
   },
-  "packageManager": "<%= packageManager %>@<%= pnpm ? '10.19.0' : npm ? '11.6.2' : 'latest' %>",
   "ember": {
     "edition": "octane"
   },