Clear pnpm-version in CI workflow

Update .github/workflows/ci.yaml to set pnpm-version to an empty string instead of `10`. This prevents the reusable plugin from forcing pnpm v10 and allows the setup action to use its default/system pnpm or to resolve the version dynamically.

Author: ruibaby

.github/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
       - uses: halo-sigs/reusable-workflows/plugin-setup-env@v4
         with:
           node-version: 24
-          pnpm-version: 10
+          pnpm-version: ''
           java-version: 21
       - name: Install dependencies
         run: pnpm install