fix: web test not install pnpm before use (#13931)

.github/workflows/web-tests.yml

@@ -32,6 +32,12 @@ jobs:
         with:
           files: web/**
 
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+          run_install: false
+
       - name: Setup Node.js
         uses: actions/setup-node@v4
         if: steps.changed-files.outputs.any_changed == 'true'