Use best practice to avoid potential attack (#24986)

Author: wyunchi-ms

.github/workflows/pr-labeled.yml

@@ -20,4 +20,6 @@ jobs:
           .github
     - name: process label
       shell: pwsh
-      run: .github/workflows/script/PrLabeled.ps1 -LabelName "${{ github.event.label.name }}" -PrUrl $env:PR
+      env:
+        LABEL: ${{ github.event.label.name }}
+      run: .github/workflows/script/PrLabeled.ps1 -LabelName "$LABEL" -PrUrl $env:PR