ci: revert workflow change, keep labeler.yml config fix only

Author: ssam18

.github/workflows/labeler.yml

@@ -11,8 +11,7 @@ jobs:
     steps:
     - uses: actions/checkout@v6
       with:
-        ref: ${{ github.event.pull_request.head.sha }}
-        repository: ${{ github.event.pull_request.head.repo.full_name }}
+        repository: "ggml-org/llama.cpp"
     - uses: actions/labeler@v6
       with:
         configuration-path: '.github/labeler.yml'