Fix PNI Playwright tests

[mmmavis]

Related #9373

This PR enables existing Playwright tests for PNI search related functionalities by fixing broken code and breaking code into individual tests using test hooks.

File is relocated under a new folder pni and renamed into search.spec.js

To test locally

• Run docker-compose up on one tab
• Approach 1:
  • On package.json, update line 52 to "playwright:integration": "wait-on -i 3000 -t 120000 -v http://127.0.0.1:8000/cms && playwright test ./tests/integration/pni" so you can skip all other tests unrelated to PNI search
  • Open a new terminal tab, and run npm run playwright:integration
• Approach 2: Alternatively, you can run the PNI tests directly using VSCode's Test Explorer.

[jhonatan-lopes]

Hey @mmmavis, thanks for this! It's working well LGTM 🚀

[jhonatan-lopes]

Another thing that I noticed here is that playwright is not installed inside the container. I think it would be better to install it alongside the dependencies of the dev Dockerfile and make sure that it runs inside the container (and with the right seed) so that we don't have tiny differences between the playwright env and the Docker env.

[jhonatan-lopes]

Ticket to clean up package.json scripts: #11767

[mmmavis]

@jhonatan-lopes thanks for the suggestions and filing follow-up ticket to make our dev setup more concrete!