feat: implement verify integrity check

[Hotell]

1. Removes invalid changefiles introduced

   • https://github.com/microsoft/fluentui-contrib/pull/143/files#diff-935baad70042ef84471b919f884a2f7b73ef42ddfd003dc059c50310b819bebe
   • https://github.com/microsoft/fluentui-contrib/pull/149/files#diff-0862bad8eb7dca9166db074d664922457daf1349e8084c75c1e29f93b6ce097a
   • 

2. introduces verify-integrity target within root repo which will be executed only if root repo files are affected