[ci skip] chore: fix incorrect commit hash in PR builds (#11198)

* fix incorrect hash in PR builds

* only apply ref on pull_request triggers

.github/workflows/build.yml

@@ -24,7 +24,12 @@ jobs:
         java: [21]
       fail-fast: true
     steps:
-      - uses: actions/checkout@v4
+      - if: ${{ github.event_name == 'push' }}
+        uses: actions/checkout@v4
+      - if: ${{ github.event_name == 'pull_request' }}
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event.pull_request.head.sha }}
       - name: JDK ${{ matrix.java }}
         uses: actions/setup-java@v4
         with: