ref(docs): update pnpm test command (#13976)

Author: michellewzhang

develop-docs/development-infrastructure/testing.mdx

@@ -363,10 +363,10 @@ See the [Frontend Handbook](/frontend/#testing) for more Jest testing tips.
 
 ```shell
 # Run jest in interactive mode
-yarn test
+pnpm test
 
 # Run a single test
-yarn test tests/js/spec/views/issueList/overview.spec.js
+pnpm test tests/js/spec/views/issueList/overview.spec.js
 ```
 
 ### API Fixtures