build(node): cleanup production deps before installing dev/production (#829)

Author: Benjamin E. Coe

synthtool/gcp/templates/node_library/.github/workflows/ci.yaml

@@ -19,7 +19,9 @@ jobs:
       # The first installation step ensures that all of our production
       # dependencies work on the given Node.js version, this helps us find
       # dependencies that don't match our engines field:
-      - run: npm install --production --engine-strict --ignore-scripts
+      - run: npm install --production --engine-strict --ignore-scripts --no-package-lock
+      # Clean up the production install, before installing dev/production:
+      - run: rm -rf node_modules
       - run: npm install
       - run: npm test
       - name: coverage