Configure GCR auth (#36678)

Author: aIbrahiim

.github/workflows/beam_PostCommit_Python_ValidatesContainer_Dataflow.yml

@@ -79,6 +79,21 @@ jobs:
         with:
           java-version: default
           python-version: ${{ matrix.python_version }}
+      - name: Authenticate to GCP
+        uses: google-github-actions/auth@v3
+        with:
+          service_account: ${{ secrets.GCP_SA_EMAIL }}
+          credentials_json: ${{ secrets.GCP_SA_KEY }}
+      - name: Set up Cloud SDK
+        uses: google-github-actions/setup-gcloud@v3
+      - name: Configure Docker auth for GCR
+        run: |
+          gcloud --quiet auth configure-docker us.gcr.io
+          gcloud --quiet auth configure-docker gcr.io
+          gcloud auth list
+      - name: Docker login to GCR (explicit)
+        run: |
+          gcloud auth print-access-token | docker login -u oauth2accesstoken --password-stdin https://us.gcr.io
       - name: Set PY_VER_CLEAN
         id: set_py_ver_clean
         run: |
@@ -105,7 +120,7 @@ jobs:
         uses: actions/upload-artifact@v4
         if: failure()
         with:
-          name: Python Test Results
+          name: Python Test Results ${{ matrix.python_version }}
           path: '**/pytest*.xml'
       - name: Publish Python Test Results
         uses: EnricoMi/publish-unit-test-result-action@v2