chore: removing the forked repo in repo.sh

Author: Sandeep C

repo.sh

@@ -336,7 +336,6 @@ FORKED_REPOS=(
     "frontend-app-enterprise-public-catalog"
     "frontend-app-publisher"
     "frontend-app-support-tools"
-    "frontend-app-admin-portal"
     "frontend-app-learner-portal-enterprise"
     "frontend-app-enterprise-checkout"
     "frontend-app-authoring"