CCM-17346: Add pnpm setup to test-unit job

Author: damientobin1

.github/workflows/stage-2-test.yaml

@@ -44,6 +44,15 @@ jobs:
     steps:
       - name: "Checkout code"
         uses: actions/checkout@v4
+      - name: "Setup pnpm"
+        uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v5.0.0
+        with:
+          version: ${{ inputs.pnpm_version }}
+      - name: "Use Node.js"
+        uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
+        with:
+          node-version-file: '.tool-versions'
+          cache: 'pnpm'
       - name: "Run unit test suite"
         run: |
           make test-unit